Multiply two digit number by 11

- Trick
- Practice

## Example 1 **53 x 11 = 583**

### Step 1 - Add both digits of the two digit number:

**5 + 3 = 8**

### Step 2 - Place the result in between both digits:

**583**Answer

## Example 2 **59 x 11 = 649**

### Step 1 - Add both digits of the two digit number:

**5 + 9 = 14**

### Step 2 - Carry the 1 when the result is greater than 9

**5 + 1 = 6**

**649**Answer

**16 x 11 =**Check **62 x 11 =**Check **84 x 11 =**Check

**54 x 11 =**Check **76 x 11 =**Check **43 x 11 =**Check

Square numbers ending in 5

- Trick
- Practice

## Example 1 **85 x 85 = 7225**

### Step 1 - Multiply the first digit by the first digit plus one:

**8 x (8 + 1) = 8 x 9 = 72**

### Step 2 - Write the number 25 next to the number from the first step:

**7225**Answer

## Example 2 **45 x 45 = 2025**

### Step 1 - Multiply the first digit by the first digit plus one:

**4 x ( 4 + 1) = 4 x 5 = 20**

### Step 2 - Write the number 25 next to the number from the first step:

**2025**Answer

**15 x 15 =**Check **65 x 65 =**Check **55 x 55 =**Check

**25 x 25 =**Check **75 x 75 =**Check **35 x 35 =**Check

Multiply two digit numbers having same tens digit and ones digits add up to 10

- Trick
- Practice

## Example 1 **38 x 32 = 1216**

### Step 1 - Multiply the first digit by the first digit plus one:

**3 x (3 + 1) = 3 x 4 = 12**

### Step 2 - Multiply the rightmost digits:

**8 x 2 = 16**

### Step 3 - Put the result from step 2 next to result from step 1:

**1216**Answer

## Example 2 **69 x 61 = 4209**

### Step 1 - Multiply the first digit by the first digit plus one:

**6 x (6 + 1) = 6 x 7 = 42**

### Step 2 - Multiply the rightmost digits:

**9 x 1 = 09 (if the result is a single digit put a 0 in front of it)**

### Step 3 - Put the result from step 2 next to result from step 1:

**4209**Answer

**43 x 47 =**Check **24 x 26 =**Check **59 x 51 =**Check

**23 x 27 =**Check **37 x 33 =**Check **94 x 96 =**Check

Square numbers in the 50’s

- Trick
- Practice

## Example 1 **58 x 58 = 3364**

### Step 1 - Add 25 to ones digit:

**25 + 8 = 33**

### Step 2 - Square the ones digit number:

**8 x 8 = 64**

### Step 3 - Place the result from step 2 next to the result from step 1 :

**3364**Answer

## Example 2 **54 x 54 = 2916**

### Step 1 - Add 25 to ones digit:

**25 + 4 = 29**

### Step 2 - Square the ones digit number:

**4 x 4 = 16**

### Step 3 - Place the result from step 2 next to the result from step 1 :

**2916**Answer

**57 x 57 =**Check **59 x 59 =**Check **52 x 52 =**Check

**51 x 51 =**Check **55 x 55 =**Check **58 x 58 =**Check

Multiply even number by 5

- Trick
- Practice

## Example 1 **242 x 5 = 1210**

### Step 1 - Divide the given number by 2:

**242/2 = 121**

### Step 2 - Write 0 next to the result from step 1 :

**1210**Answer

## Example 2 **112 x 5 = 560**

### Step 1 - Divide the given number by 2:

**112 / 2 = 56**

### Step 2 - Write 0 next to the result from step 1 :

**560**Answer

**106 x 5 =**Check **612 x 5 =**Check **216 x 5 =**Check

**602 x 5 =**Check **84 x 5 =**Check **76 x 5 =**Check