# Math Hacks to Conquer Mental Math In No Time

No math gene? Just a little bit of practice every day will help you solve math problems quickly in your head! Explore the math hacks that will help you do mental math within mere seconds.

## Math Hack #1 Simple multiplication by 11

Multiplication by 11 is so easy that you will be able to do mental multiplication within seconds.

Below is the easiest way to multiply two-digit numbers by 11 in just two steps.

### 35 x 11=?

Solution: Add 3 and 5 to get 8. Put 8 in between 3 and 5 to get 385.

Ta-da! You’ve solved the problem!

But what if the sum of the two digits happens to be greater than 9? Let’s modify the trick a bit so that it suits our purpose.

### 79 x 11=?

Solution: Add the two digits: 7+9=16 Put 6 in between 7 and 9 to get 769 Add the 1 from 16 and the 7 from 769 to get 869.

Pretty easy, isn’t it?

### Math Hack #2 Subtraction from 1,000, 10,000, 100,000, etc.

Subtracting from 1,000, 10,000, or even 100,000 is no longer a nightmare with this simple math-hack.

### 1,000 – 547 =?

Solution: Subtract all but the last digit of the subtrahend from 9: 9-5=4 and 9-4=5 Subtract the last digit from 10: 10-7=3

## Math Hack #3 Fast Addition Technique

### 88+7=?

Solution: You need to add 2 to 88 to round it to the nearest ten, which in this case is 90. Thus, break 7 into 2 and 5. First, add 2 to 88 to get 90, then complete the addition by adding 5 to 90: 88+2+5=90+5=95

When adding two-digit numbers, consider the place value of each digit.

### 56+38=?

Solution: Break the numbers apart by their place value: 56 is 5 tens and 6 ones and 38 contains 3 tens and 8 ones. Add the digits according to their place value: 50+30=80 (tens) and 6+8=14(ones) Complete the addition: 80+14=94

The same technique can also be used for larger numbers, though it will involve more steps to solve a math problem.

## Math Hack #4 Easy way to divide by 5

Ready for more? Let’s see how to divide any large number by 5 quickly.

### 433/5=?

Solution: Multiply 433 by 2 to get 866 Move the decimal point one place to the left to get 86.6.

Now let’s find out how a bit of algebra makes squaring two-digit numbers much easier.

### 322=?

Solution: Let’s break 32 into 30 and 2 to make it fit the formula (a+b)2=a2+2ab+b2. Do the calculations: (30+2)2=302+2x30x2+22=900+120+4=1,024.

## Math Hack #6 Multiply by 4 in seconds

Have a look at a simple multiplication hack based on the expression 2x2=4.

### 51 x 4=?

Solution: Double 51 to get 102 Add 102 and 102 to get 204