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Easy Math Tricks You'll Wish You'd Known
Put the calculator away—with these simple tricks you'll be able to solve most problems in a jiffy.
Every editorial product is independently selected, though we may be compensated or receive an affiliate commission if you buy something through our links. Ratings and prices are accurate and items are in stock as of time of publication.
Nicole Fornabaio/rd.com
Making math easy
Juggling numbers isn’t everyone’s forte—even though math manages to sneak its way into our everyday lives. Fortunately, these easy-to-remember math tricks will be your best friend next time you’re faced with a tricky equation and don’t have a calculator handy. Also, don’t miss these math lessons you’ll actually end up using in real life.
Nicole Fornabaio/rd.com
Finding a 20 percent tip
Did you enjoy your dining service? Leave your server a 20 percent tip with this easy math trick. According to Kate Snow, author of The Math Facts That Stick series, all you have to do is divide your check amount by five. For example, if your check comes to $85, divide that by five and your 20 percent tip will be $17. For more on tipping, here’s our guide on how much to tip in every situation.
Nicole Fornabaio/rd.com
Multiplying two-digit numbers by 11
Multiplying two-digit numbers by 11 is a breeze with this clever trick from math.hmc.edu. Simply add the two digits together and place the sum in the middle. For example, if you’re multiplying 25 by 11, add the two and five together to get seven, and place the seven between those two numbers to find the final answer, which is 275. While we’re discussing math, try solving this second-grade math problem no one can figure out.
Nicole Fornabaio/rd.com
Doubling
To double a large number, multiply each individual number by two and add them together. Snow suggests starting from the left to make it easier to keep track of the numbers. “For example, to double 147, start with the hundreds place. Double 100 is 200. Double 40 is 80. Double seven is 14. Add them all up (200 plus 80 plus 14) and you get 294,” says Snow. If you think you’re a math expert, try out these arithmetic problems.
Nicole Fornabaio/rd.com
Multiplying numbers that end in zero
Even equations involving large, intimidating numbers that end in zero can be easily solved with this handy trick. According to education.cu-portland.edu, just exclude the zeros from the equation, then add them back in afterward. For example, if you’re multiplying 600 by 400, exclude the zeros and solve for six times four, which is 24.
After, count the total number of zeros that were in the original equation and tack them onto the number you solved for to find your final answer. Since there were four zeros in the original equation, your final answer for this example is 240,000. This is how mental math works.
Nicole Fornabaio/rd.com
Multiplying by nine
If you don’t have your nines times table memorized, not to worry. According to Snow, to multiply by nine, simply multiply the number by 10 first, then subtract the original number. For example, if you need to multiply nine by 23, multiply 23 by 10 to find 230. Then, subtract 23 from 230 to find your final answer of 207. We know, math can be a headache—but these clever math jokes are even hilarious to non-mathematicians.
Nicole Fornabaio/rd.com
Dividing by 10, 100, or 1,000
To divide a number by 10, all you need to do is move the decimal place one spot to the left of the original number to find your answer, according to Snow.
To divide by 100, the same idea applies, except you’ll move the decimal place two spots to the left of the original number. As for dividing by 1,000, move the decimal place three spots to the left. For example, if you’re dividing 42.94 by 10, you simply move the decimal place one spot to the left to find your final answer of 4.294.
Nicole Fornabaio/rd.com
Multiplying by 10, 100, or 1,000
Similar to how you divide a number by 10, 100, or 1,000, Snow says you’ll need to do the opposite to multiply by them. To multiply a number by 10, move the decimal place one spot to the right. To multiply a number by 100, move the decimal place two spots to the right. To multiply a number by 1,000, move the decimal place three spots to the right. For example, if you need to multiply 366.78 by 100, shift the decimal place two spots to the right to find your final answer of 36,678. By the way, if you can solve this math problem on the first try, you might be a genius.
Nicole Fornabaio/rd.com
Turning a repeating fraction into a decimal
According to businessinsider.com, there are three steps you’ll need to follow to easily turn a repeating decimal into a fraction. First, find the number that is repeating. For example, in the number 0.636363…, 63 is the repeating number. Then, figure out how many places that number has. In this example, 63 has two places. Finally, divide the repeating number by a number that has the same amount of places made up by nines, which would be 99 in this case. Reduce the fraction of 63/99 to 7/11—and done.
Nicole Fornabaio/rd.com
Multiplying by 25
Not everyone has their 25 times table memorized, but that’s not a problem when you think of each group of 25 as a quarter. “If you had 17 quarters, how much money would you have? Every four quarters make a dollar, so 16 of the quarters equals four dollars or 400 cents.
The extra quarter adds 25 cents, for a total of 425 cents,” Snow explains.
Nicole Fornabaio/rd.com
Squaring numbers that end in five
This math trick requires two steps, says Snow. In order to square a number that ends in five, take the first digit of the number and multiply it by itself. After, add the result to itself for the answer. For example, if you’re multiplying 35 by 35, take the three and multiply it by itself, which is nine, then add three to that answer, which is 12. Finally, add the number 25 to the end of the number you found and that is the final answer: 1,225. Feeling like a math expert? Put your skills to the test and try to pass this math test for fifth graders.
Nicole Fornabaio/rd.com
Subtracting by adding
If you find addition to be a little easier than subtraction, this trick is for you. If you are dealing with subtracting two numbers that are fairly close together, try solving the equation by adding instead.
“Instead of trying to take away 327 from 334, think of it as ‘327 plus how many more equals 334?'” says Snow. Can you pass this elementary school math test?
Nicole Fornabaio/rd.com
Adding 99
If you’re trying to figure out exactly how much your groceries will cost when most of the items end in .99 cents, no calculator is necessary. All you have to do is add 100 instead of 99 and then subtract one. Snow explains this process with the example 176 plus 199 equals 375. “176 plus 200 equals 376,” she says. “Since you added one more than you need, subtract one from 276 to find the answer: 275.”
Sources:
- Kate Snow, author of The Math Facts That Stick series
- CU-Portland.edu: “10 Tricks for Doing Fast Math”
- Business Insider: “10 Mental Math Tricks That Will Make You Wildly Popular At Parties”
Originally Published: November 23, 2020
Brittany Gibson
Brittany Gibson is a regular contributor to RD.
com’s culture, food, health, and travel sections. She was previously an editorial intern for RD.com and Westchester Magazine. Her articles have appeared on Buzzfeed, Business Insider, AOL, Yahoo, and MSN, among other sites. She earned a BA in English from the University of Connecticut.
Tape | Simple Math with Ribbon!
Croissant 7DAYS
Midi cocoa (Russia) 65g
Cake BARNIE BEAR
biscuit with chocolate filling (Russia) 30g
Cookies OREO
(Russia) 95g
Cookies MILKA
with chocolate chips (Poland) 168g
Croissant 7DAYS
Midi vanilla (Russia) 65g
Cake Bar 7DAYS
Cake Bar with vanilla cream glazed (Russia) 35g
Croissant 7DAYS
Vanilla cream 3+1 4x65g (Russia) 260g
Croissant 7DAYS
Cocoa cream 3+1 4x65g (Russia) 260g
Cake Bar 7DAYS
Cake Bar with strawberry jam (Russia) 30g
Croissants 7DAYS
Mini cocoa (Russia) 300g
Croissants 7DAYS
Mini boiled condensed milk (Russia) 300g
Croissants 7DAYS
Mini vanilla (Russia) 300g
Croissants 7DAYS
Hazelnut with cream (Russia) 260g
Croissants 7DAYS
Hazelnut with cream (Russia) 65g
Croissants 7DAYS
Mini cocoa vanilla 300g (Russia) 300g
Croissants 7DAYS
Mini vanilla-cherry (Russia) 300g
Mini croissants 7DAYS
With vanilla cream (Russia) 105g
Mini croissants 7DAYS
With cocoa cream (Russia) 105g
Mini croissants 7DAYS
With cream boiled condensed milk (Russia) 105g
Mini croissants 7DAYS
With strawberry filling (Russia) 105g
Croissants 7DAYS
with cream Boiled condensed milk 3+1 (Russia) 260g
Croissant 7DAYS
with double vanilla-cherry filling (Russia) 110g
Croissant 7DAYS
with cocoa-vanilla double cream (Russia) 110g
Croissant 7DAYS
with cocoa cream (Russia) 110g
Croissant 7DAYS
Assorted berries (Russia) 65g
Strudel 7DAYS
Apple-cinnamon (Russia) 80gx3
Biscuit cake 7DAYS
Cake Bar unglazed.
from the beginning cocoa 5x30g (Russia) 150g
Biscuit cake 7DAYS
Cake Bar unglazed. from the beginning strawberries 5x30g (Russia) 150g
Cookies 7DAYS
with cocoa cream (Russia) 100g
Cookies 7DAYS
with vanilla cream (Russia) 100g
Cookies 7DAYS
with chocolate glaze and cocoa cream (Russia) 100g
Biscuit roll 7DAYS
with cream boiled condensed milk (Russia) 300g
Biscuit roll 7DAYS
with strawberry filling (Russia) 300g
Biscuit roll 7DAYS
with cappuccino cream (Russia) 300g
Biscuit roll 7DAYS
with cocoa cream (Russia) 300g
Biscuit cake 7DAYS
Cake Bar unglazed with cocoa cream (Russia) 30g
Croissants 7DAYS
Mini cocoa (Russia) 65g
Strudel 7DAYS
with apricot filling (Russia) 80g
Strudel 7DAYS
with apple-cinnamon filling (Russia) 80g
Cake BEAR BARNIE
Biscuit bear with chocolate filling (Russia) 150g
Cake BEAR BARNIE
biscuit with milk filling (Russia) 150g
BARNIE BEAR Cake
biscuit with banana-yoghurt filling (Russia) 150g
Cake BARNIE BEAR
biscuit with condensed milk filling (Russia) 150g
Biscuit cake with strawberry and vanilla filling (Russia) 150g
BARNIE BEAR Cake
biscuit with chocolate and nut filling (Russia) 150g
Biscuit cake BEAR BARNIE
with milk filling (Russia) 240g
Biscuit cake BEAR BARNIE
with chocolate filling (Russia) 240g
Cake BARNEY BEAR
Fan Sandwich from the beginning.
with a piece topics. shock. original taste (Poland) 180g
Cake BARNEY BEAR
Fan Sandwich with cocoa and early. with a piece topics. shock. (Poland) 180g
BARNIE BEAR cake
Duo teddy bear with raspberries. early with coconut flavor (Poland) 150g
Cake BEAR BARNIE
biscuit with milk filling (Russia) 30g
Cake BARNEY BEAR
Fan Sandwich with chopped. oven OREO and from the beginning. with a piece topics. shock. (Poland) 180g
Biscuit cake BARNIE BEAR
Fan Sandwich stuffed with dark chocolate pieces (Poland) 180g
Biscuit cake BARNIE BEAR
Fan Sandwich with cocoa stuffed with dark chocolate pieces (Poland) 180g
Cakes BEAR BARNIE
with chocolate and milk filling (Russia) 180g
Biscuit cake BARNIE BEAR
Fan Sandwich with crushed OREO biscuits and with chocolate chips (Poland) 180g
Cake BARNIE BEAR
With banana and yoghurt filling with a toy (Russia) 90g
Cake BARNIE BEAR
With banana-yoghurt filling (Russia) 90g
BARNIE BEAR set
Chocolate/Milk/banana-yoghurt stuffing with toy (Russia) 90g
Biscuits BEAR BARNIE
with raspberry and coconut flavored filling (Poland) 150g
BARNIE BEAR Cake
with shock.
stuffing (Russia) 720g
Cake BEAR BARNIE
Assorted car (Russia) 180g
Cake BEAR BARNIE
with orange filling and cinnamon biscuit (Russia) 150g
Cake BEAR BARNIE
Assorted steam locomotive biscuit (Russia) 180g
Biscuit cake BARNEY BEAR
Oreo from the beginning. cocoa and vanilla taste (Russia) 196g
Cookies OREO
(Russia) 228g
Cookies OREO
(Russia) 38g
Cookies OREO
with cocoa and filling with chocolate flavor (Russia) 95g
OREO biscuits
with cocoa and filling with chocolate flavor (Russia) 228g
Cookies OREO
with cocoa and double filling with vanilla (Spain) 170g
Cookies OREO Mini
with cocoa and vanilla flavored filling (Spain) 100g
OREO biscuits
Golden early with vanilla taste (Czech Republic) 176g
Cookies OREO
with cocoa filling with vanilla flavor and chocolate flavor filling (Russia) 456g
Cookies OREO
in milk chocolate (Spain) 246g
Cookies OREO
with cocoa and filling with strawberry flavor (Russia) 228g
Cookies OREO
with cocoa and filling with strawberry flavor (Russia) 95g
OREO biscuits
with cocoa with incl.
caramel and colored confectionery topping (Spain) 176g
OREO biscuits
with cocoa and vanilla cream filling (Czech Republic) 396g
OREO biscuits
Mini Golden with vanilla flavored filling (Spain) 100g
Cookies OREO
with cocoa and orange filling with vanilla flavor (Spain) 154g
OREO biscuits
with cocoa and orange flavor filling (Egypt) 95g
Biscuit MILKA
with chocolate pieces (Poland) 175g
MILKA biscuits
glazed chocolate (Poland) 200g
Cake MILKA
Сhoc and Choc (Poland) 150g
Cookies MILKA
With milk filling covered with chocolate (Czech Republic) 150g
Cookies MILKA
Sensations with filling (Poland) 156g
Biscuit MILKA
Lila Cake with milk chocolate and biscuit with cocoa (Poland) 140g
Cookies MILKA
with oatmeal, covered with milk chocolate (Poland) 168g
Nut paste MILKA
With cocoa (Belgium) 350g
Cookies MILKA
Sensations with cocoa and milk chocolate (Poland) 156g
Wafers MILKA
With cocoa filling covered with milk chocolate (Czech Republic) 150g
MILKA Cookies
Mini Cookies with cous.
shock. partially covered mol. chocolate (Spain) 100g
Wafers MILKA
With cocoa filling, covered with milk chocolate (Czech Republic) 30g
Cookies MILKA
With oatmeal, covered with milk chocolate (Poland) 42g
MILKA biscuits
Crunchy Break with milk chocolate filling (Czech Republic) 26g
Nut paste MILKA
with cocoa (Belgium) 600g
Wafers MILKA
with cocoa filling covered with white chocolate (Czech Republic) 180g
Wafers MILKA
with cocoa filling covered with milk chocolate (Czech Republic) 180g
MILKA wafers
with cocoa/mol.
shock. and oreo cookies with vanilla (Russia) 174g
Wafers MILKA
with cocoa/white shock. and oreo cookies with strawberry flavor (Russia) 174g
Cookies MILKA
with milk start coating (Czech Republic) 187g
Cookies MILKA
Sensations cocoa with filling (Poland) 156g
MILKA biscuits
Biscuits choco pause with mol. shock. (Spain) 260g
Set MILKA
Cookies Flower (Czech Republic) 150g
Milk chocolate MILKA
with caramel filling (Russia) 90g
Milk chocolate MILKA
LU with cookies (Russia) 87g
Chocolate MILKA
Milk chocolate with salty crackers Tuc (Russia) 87g
Milk chocolate MILKA
with Oreo cookies with vanilla flavor filling (Hungary) 92g
Chocolate MILKA
milk peanuts/karam/rice ball corn cotton (Bulgaria) 90g
Chocolate MILKA
Bubbles porous milk chocolate with coconut filling (Russia) 92g
Milk chocolate MILKA
with two-layer filling: mind.
and forest. berries (Russia) 85g
Milk chocolate MILKA
milky with added nuts. hazelnut paste and crushed fund. (Russia) 85g
MILKA chocolate
MILKA Bubbles white porous chocolate with crushed nuts (Russia) 79g
Milk chocolate MILKA
(Russia) 85g
Chocolate MILKA
Bubbles porous milk chocolate with banana-yoghurt filling (Russia) 92g
Chocolate MILK
Bubbles porous milk chocolate with cappuccino flavor filling (Russia) 92g
Milk chocolate MILKA
with crushed hazelnuts and raisins (Russia) 85g
Milk chocolate MILKA
with crushed nuts (Russia) 85g
Milk chocolate MILKA
with whole hazelnuts (Russia) 85g
Milk chocolate MILKA
with whole almonds (Russia) 85g
Milk chocolate MILKA
Bubbles porous milk (Russia) 76g
Milk chocolate MILKA
With added nut paste and caramelized almonds (Russia) 85g
Milk chocolate MILKA
With two-layer strawberry and cream filling (Russia) 85g
Milk chocolate MILKA
Oreo with round biscuits with strawberry flavor filling (Russia) 92g
Candies MILKA
Thank you Milk Cream with praline filling (Bulgaria) 110g
Candies MILKA
I Love Milka Hazelnut with nut filling (Bulgaria) 110g
Chocolate MILKA
milk caramel.
early peanut air rice and peanuts (Bulgaria) 276g
Milk chocolate MILKA
with milk and caramel fillings and whole hazelnut roast (Austria) 300g
Chocolate MILKA
Milk chocolate with vanilla flavor filling and biscuits (Austria) 300g
Chocolate MILKA
Milk Strawberry Cheesecake with filling (Austria) 300g
Chocolate MILKA
with chocolate and milk fillings and biscuits (Austria) 300g
Chocolate MILKA
with vanilla flavored filling and Oreo biscuit pieces (Poland) 37g
Milk chocolate MILKA
With peanuts in caramel filling (Bulgaria) 37g
Mathematics from scratch.
Step-by-step study of mathematics “Mathematics from scratch. Step by Step Math for Beginners is a new project designed for people who want to learn math on their own from scratch.
Let's say right away that there are no easy solutions and statements like “ Buy this book and pass math for 5” or “ Master math for 12 hours ” you will not see here. Mathematics is a big science that should be mastered consistently and very slowly.
The site presents math lessons, which are arranged according to the principle “from simple to complex”. Each lesson covers one or more topics from mathematics. Lessons are broken down into steps. Start learning from the first step and then ascending.
Every lesson passed must be learned. Therefore, without understanding one lesson, you cannot move on to the next, since each lesson in mathematics is based on understanding the previous one. If you didn’t understand the lesson the first time, don’t be discouraged.
Be aware that some people have taken months and years to understand just one single topic. Despair and despondency are definitely not your way. Read, study, try and try again.
Mathematics is well learned when a person opens a textbook on his own and teaches himself. At the same time, a certain discipline is developed, which is very helpful in the future. If you stick to the principle "from simple to complex", you will be surprised to find that mathematics is not so difficult. Perhaps even it will seem interesting and exciting to you.
What will the knowledge of mathematics give you? First, confidence. Not everyone knows mathematics, so knowing that you know at least some part of this serious science makes you special. Secondly, having mastered mathematics, you can easily master other sciences and be able to think much more broadly. Knowledge of mathematics allows you to master such professions as a programmer, accountant, economist. No one will argue that these professions are in great demand today.
In general, go for it friend!
We wish you good luck in learning mathematics!
- Step 1. Numbers
- Step 2: Basic Operations
- Step 3 Expressions
- Step 4. Substitutions in expressions
- Step 5 Beginner Shocks
- Step 6. Multiply
- Step 7: Divide
- Step 8: Procedure
- Step 9. Mathematics
- Step 10 Divisors and Multiples
- Step 11 GCD and NOC
- Step 12. Fractions
- Step 13. Working with fractions
- Step 14 Mixed Numbers
- Step 15. Compare fractions
- Step 16 Units
- Step 17: Apply fractions
- Step 18. Decimals
- Step 19: Working with Decimals
- Step 20 Use Decimals
- Step 21 Rounding Numbers
- Step 22. Periodic fractions
- Step 23: Unit Conversion
- Step 24 Ratios
- Step 25. Proportion
- Step 26.
Distance, speed, time - Step 27. Direct and inverse proportionality
- Step 28. Interest
- Step 29 Negative Numbers
- Step 30 Modulo
- Step 31. What is a set?
- Step 32. Adding and Subtracting Integers
- Step 33. Multiplication and division of integers
- Step 34 Rational Numbers
- Step 35. Comparing Rational Numbers
- Step 36. Adding and subtracting rational numbers
- Step 37. Multiplying and dividing rational numbers
- Step 38: Learn more about fractions
- Step 39 Letter Expressions
- Step 40. Bracketing the common factor
- Step 41. Opening the brackets
- Step 42: Simple Math Problems
- Step 43. Fraction Problems
- Step 44 Interest Problems
- Step 45. Movement tasks
- Step 46 Performance
- Step 47. Statistics elements
- Step 48 Understanding Equations
- Step 49: Solving Problems with Equations
- Step 50 Solving Problems with Proportion
- Step 51.
Systems of Linear Equations - Step 52 Understanding Inequalities
- Step 53. Systems of linear inequalities with one variable
- Step 54. Set Operations
- Step 55. Degree with natural indicator
- Step 56. Degree with integer exponent
- Step 57. Perimeter, area and volume
- Step 58. Monomials
- Step 59 Polynomials
- Step 60: Reduced Multiplication Formulas
- Step 61. Factoring a polynomial
- Step 62. Division of polynomials
- Step 63. Identity transformations of polynomials
- Step 64 Square Root
- Step 65. Square Root Algorithm
- Step 66 Quadratic Equation
- Step 67. Quadratic equation with even second coefficient
- Step 68. Vieta's theorem
- Step 69. Factoring the square trinomial
- Step 70. Generalized concept of the modulus of a number
- Step 71 Equation with modulo
- Step 72.
