Are you ready to give your mathematics skills a boost? These simple math tricks can help you perform calculations more quickly and easily. They also come in handy if you want to impress your teacher, parents, or friends.
1. Multiplying by 6
If you multiply 6 by an even number, the answer will end with the same digit. The number in the ten’s place will be half of the number in the one’s place.This ploy works effortlessly and students can add it to their collection of maths magic tricks!
This is probably the most fun tricks in maths -to remember the first seven digits of pi, count the number of letters in each word of the sentence:
“How I wish I could calculate pi.”
This becomes 3.141592.
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.
Finger Multiplication Tables
Everyone knows you can count on your fingers. Did you realize you can use them for multiplication? A simple maths magic trick to do the “9” multiplication table is to place both hands in front of you with fingers and thumbs extended. To multiply 9 by a number, fold down that number finger, counting from the left.
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.
Adding large numbers
Adding large numbers just in your head can be difficult. This method shows how to simplify this process by making all the numbers a multiple of 10. Here is an example:
644 + 238
While these numbers are hard to contend with, rounding them up will make them more manageable. So, 644 becomes 650 and 238 becomes 240.
Now, add 650 and 240 together. The total is 890. To find the answer to the original equation, it must be determined how much we added to the numbers to round them up.
650 – 644 = 6 and 240 – 238 = 2
Now, add 6 and 2 together for a total of 8
To find the answer to the original equation, 8 must be subtracted from the 890.
890 – 8 = 882
So the answer to 644 +238 is 882.
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.
Subtracting from 1,000
Here’s a basic rule to subtract a large number from 1,000: Subtract every number except the last from 9 and subtract the final number from 10
1,000 – 556
Step 1: Subtract 5 from 9 = 4
Step 2: Subtract 5 from 9 = 4
Step 3: Subtract 6 from 10 = 4
The answer is 444.
When multiplying large numbers, if one of the numbers is even, divide the first number in half, and then double the second number. This method will solve the problem quickly.
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.
The 11 Rule
The 11 rule is one of those magic tricks and methods that can be used to quickly multiply two-digit numbers by 11 in your head.
Separate the two digits in your mind.
Add the two digits together.
Place the number from Step 2 between the two digits. If the number from Step 2 is greater than 9, put the one’s digit in the space and carry the ten’s digit.
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 Stickseries, 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..