## The numbers addition to perform:

51 + 90

#### Method used below: column adding, from right to left (traditional).

### Stack the numbers on top of each other.

#### The ones digits line up in the first column from the right.

#### The tens digits line up in the next column to the left.

## Add column by column; start from the column on the right.

### Add the digits in the ones column:

#### 1 + 0 = 1

#### 1 is the ones digit.

Write it down at the base of the ones column.

### Add the digits in the tens column:

#### 5 + 9 = 14

#### How did we add the digits? Explanation below.

#### Group the ones together in order to make tens:

#### 5 + 9 =

#### 5 + 9 =

#### 1 + 4 + 9 =

#### 1 + 4 + 9 =

#### (1 + 9) + 4 =

#### 10 + 4 =

#### 14

#### Change the order in which the numbers are added, the sum stays the same.

Break some number(s) into component parts, the sum stays the same.

#### The sum is a two-digit number: 14.

#### 4 is the tens digit.

Write it down at the base of the tens column.

#### 1 is the hundreds digit.

Write it down at the base, next to the tens digit.

## Answer: