Many students, even parents and some teachers assume mathematics is such a difficult subject that’s meant for certain set of individuals. That’s not true! Turns out math is one of the simplest subjects anyone can ace if s/he learns the tricks and is determined to excel in Math. The first step to be outstanding in math is to know the rudiments behind addition, subtraction, division and multiplication. They are the basis on which all math theories are based.
That said, learning tricks on how to do mathematics quickly can help students develop greater confidence in math and excel in advanced courses.
Here are 10 fast math tricks everyone can use to do math faster without necessarily using a calculator. Once these strategies are mastered, students should be able to accurately and confidently solve math problems. Parents can also use the techniques in their day-to-day business dealings.
- Trick for adding large numbers
When you have large numbers to add, the best trick is to make all the numbers a multiple of 10. Example:
457 + 316
While these numbers are hard to contend with, rounding them up will make them more manageable. So, 457 becomes 460 and 316 becomes 320.
You will agree that it’s easier to sum 460 and 320 together. The total is 780.
Now to find the answer of the original equation, you must determine how much you added to or subtracted from the numbers to round them up.
460 – 457 = 3, and 320 – 316 = 4
Now, add 3 and 4 together for a total of 7
To find the answer to the original equation, 7 must be subtracted from the 780.
780 – 7 = 773
So the answer to 457 + 316 = 773
- Trick for subtracting a large number from 1,000
Subtract every number except the last from 9 and subtract the final number from 10
1,000 – 627
Step 1: Subtract 6 from 9 = 3
Step 2: Subtract 2 from 9 = 7
Step 3: Subtract 7 from 10 = 3
The answer is 373.
- Trick for multiplying an even number by 5
Take the number being multiplied by 5 and cut it into half. Then include zero in the result.
Example: 62 x 5
Just divide 62 by 2. That gives you 31. Then include zero. That makes 310.
- Trick for multiplying an odd number by 5
Subtract one from the number being multiplied by 5, Halve the result, then include 5 as the last digit.
Example: 43 x 5
Remove 1 from 43. That becomes 42
Half of 42 is 21
Include 5 as last digit of 21. It becomes 215
So, 43 x 5 equals 215
- Division tricks for these set of numbers
Here’s a quick way to know when a number can be evenly divided by these certain numbers:
- 2 if it ends in 0, 2, 4, 6, or 8
- 3 when the digits are added together and the result is evenly divisible by the number 3
- 4 if it ends in 00 or a two digit number that is evenly divisible by 4
- 5 if it ends in a 0 or 5
- 6 if it is an even number and when the digits are added together the answer is evenly divisible by 3
- 8 if the last three digits are evenly divisible by 8 or are 000
- 9 when the digits are added together and the total is evenly divisible by 9
- 10 if the number ends in 0
- Trick for multiplying any number by 10
The trick to multiplying any number by 10 is to add a zero to the end of the number. For example, 750 x 10 = 7500.
- Trick for multiplying 2-digit number by 11
Take the original two-digit number and put a space between the digits. In this example, that number is 25.
Now add those two numbers together and put the result in the center:
2_(2 + 5)_5
The answer to 11 x 25 is 275.
If the numbers in the center add up to a number with two digits, insert the second number and add 1 to the first one. Here is an example for the equation 11 x 88
(8 + 1)_6_8
There is the answer to 11 x 88: 968
Finding a percentage of a number can be somewhat tricky, but thinking about it in the right terms makes it much easier to understand. For instance, to find out what 5% of 235 is, follow this method:
- Step 1: Move the decimal point backward by one place, 235 becomes 23.5.
- Step 2: Divide 23.5 by the number 2, the answer is 11.75. That is also the answer to the original equation.
- Tough multiplication
When multiplying large numbers, if one of the numbers is even, divide the first number into half, and then double the second number. This method will solve the problem quickly. For instance, consider
18 x 15
Step 1: Divide the 18 by 2, which equals 9. Double 15, which equals 30.
Then multiply your two answers together.
9 x 30 = 270
The answer to 18 x 15 is 270.
- Multiplying numbers that end in zero
Multiplying numbers that end in zero is actually quite simple. It involves multiplying the other numbers together and then adding the zeros at the end. For instance, consider:
700 x 200
Step 1: Multiply the 2 times the 4
7 x 2 = 16
Step 2: Put all four of the zeros after the 16
700 x 200 = 160,000
Practicing these fast math tricks can help both students and teachers improve their maths skills and become secure in their knowledge of mathematics—and unafraid to work with numbers in the future.