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# Addition And Subtraction Of Two-Digit Numbers

## What are two-digit numbers?

Two-digit numbers begin with 10 and end at 99. The digits in the tens position of a two-digit number must be between 1 and 9. The largest two-digit number is 99 and the least two-digit number is ten.

The place value of a number is the position of each digit. When dealing with two-digit numbers, we have two distinct place values called the ones and tens place.

Consider the number 86.

In the given example, 8 is at the tens place which means the value is 80 and 6 is at the one place, which has the value of 6.

## How to add two-digit numbers?

Whenever we add two-digit numbers, we always start the process at the outmost right digit, or the ones place.

### Adding two-digit numbers without regrouping

To add two-digit numbers, follow these steps:

1. Write the numbers with the place values lines up.
2. Add the digits in the ones place.
3. Add the digits in the tens place.

Example #1

What is the sum of 13 and 11?

Solution

Example #2

Find the sum of 24 and 33.

Solution

Example #3

Determine the sum of 16 and 42.

Solution

Example #4

What is the result when 21 is added to 58?

Solution

Example #5

What is the result of adding 73 and 22?

Solution

### Adding two-digit numbers with regrouping

To add two-digit numbers that need regrouping, follow these steps:

1. Write the numbers with the place values lines up.
2. Add the digits in the ones place. If the sum exceeds 10, then carry over the digit to the tens place.
3. Add the digits in the tens place. If the sum exceeds 10, then carry over the digit to the hundreds place.

Example #1

What is the sum of 23 and 19?

Solution

Example #2

Determine the result of adding 48 and 36.

Solution

Example #3

What is the result of adding 56 and 63?

Solution

Example #4

What is the sum of 73 and 87?

Solution

Example #5

Find the sum of 98 and 19.

Solution

## How to subtract two-digit numbers?

Whenever we subtract two-digit numbers, we always start the process at the outmost right digit, or the ones place.

### Subtracting two-digit numbers without regrouping

To subtract two-digit numbers, follow these steps:

1. Arrange the numbers one above the other so that the tens’ and ones’ place digits are aligned.
2. Subtract the units digit of the number on the second row from the units digit of the number on the first row.
3. Subtract the tens digit of the number on the second row from the tens digit of the number on the first row.

Example #1

What is the difference between 45 and 14?

Solution

Example #2

Determine the result of subtracting 59 from 99.

Solution

Example #3

Find the difference of 63 and 21.

Solution

Example #4

What is the result of 84 – 33?

Solution

Example #5

Find the difference of subtracting 18 from 79.

Solution

### Subtracting two-digit numbers with regrouping

To subtract two-digit numbers, follow these steps:

1. Arrange the numbers one above the other so that the tens’ and ones’ place digits are aligned.
2. Subtract the units digit of the number on the second row from the units digit of the number on the first row. If the units digit of the subtrahend is greater than the units digit of the minuend, then borrow 1 in the tens digit.
3. Subtract the tens digit of the number on the second row from the tens digit of the number on the first row. If the tens digit of the subtrahend is greater than the units digit of the minuend, then borrow 1 in the hundreds digit.

Example #1

What is the difference of 33 and 17?

Solution

Example #2

Find the result of subtracting 13 from 21.

Solution

Example #3

Determine the difference of subtracting 25 from 91.

Solution

Example #4

What is the difference of 87 – 59?

Solution

Example #5

Find the difference between 76 and 49.

Solution