5 Math Tips and Tricks
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
Example: 6 x 6 = 36
2. Memorizing Pi.
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.
3. Finger Multiplication Tables.
Everyone knows you can count on your fingers. Did you realize you can use them for multiplication? A simple math 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.
Example1: To multiply 9 by 5, fold down the fifth finger from the left. Count fingers on either side of the “fold” to get the answer. In this case, the answer is 45.
Example2: To multiply 9 times 6, fold down the sixth finger, giving an answer of 54.
4. Multiplying 5 times any number.
When multiplying the number 5 by an even number, there is a quick way to find the answer.
Example1: For example, 5 x 4 =
Step 1: Take the number being multiplied by 5 and cut it in half, this makes the number 4 become the number 2.
Step 2: Add a zero to the number to find the answer. In this case, the answer is 20.
5 x 4 = 20
Example2: When multiplying an odd number times 5, the formula is a bit different.
For instance, consider 5 x 3.
Step 1: Subtract one from the number being multiplied by 5, in this instance the number 3 becomes the number 2.
Step 2: Now halve the number 2, which makes it the number 1. Make 5 the last digit. The number produced is 15, which is the answer.
5 x 3 = 15.
5. Tough multiplication.
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.
Example: For instance, consider 20 x 120
Step 1: Divide the 20 by 2, which equals 10. Double 120, which equals 240.
Then multiply your two answers together.
10 x 240 = 2400
The answer to 20 x 120 is 2,400.
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