The most common way to add 3 digit numbers is to add the ones, tens, and hundreds separately. You can also add three digit numbers in a variety of other ways. Watch the videos and choose the one that works best for you!

Use base 10 models

Jump a number line

You can also use a number line to help you add numbers. You might find it easiest to add the hundreds tens, and ones separately. Watch how in this video.

Using Columns

Columns can help you organize your work. Follow the video below to see how.

Subtracting 3 Digit Numbers

You can use the same models as above to subtract three digit numbers.

Remember!

When subtracting, order matters. Subtract the second number from the first.

Base 10 models

Jump a number line

You model subtraction with a number line just like addition. Remember to move the opposite direction because subtraction is the opposite of addition.

Remember!

When adding along the number line, move to the right.

When subtracting along the number line, move to the left.

Worked Examples

Question 1

Find the value of $270+520$270+520.

Question 2

$803-500$803−500

QUESTION 3

Quiana and Kenneth are looking to buy a new pool table. Quiana has $\$165$$165 and Kenneth has $\$560$$560. How much money do they have altogether?

Outcomes

NA3-1

Use a range of additive and simple multiplicative strategies with whole numbers, fractions, decimals, and percentages.

NA3-6

Record and interpret additive and simple multiplicative strategies, using words, diagrams, and symbols, with an understanding of equality