Three-Digit Addition Worksheets

Using this page

Three-digit numbers added in columns, such as 356 + 478, with carrying in the ones, the tens or both. Grade 3 in the Common Core asks for fluent addition within 1000, and Australian students work with three-digit numbers from around Year 3. Choose 'with regrouping' for a full workout, 'no regrouping' for a gentle start, or a mix. Suits around Year 3 and Year 4 in Australia and Grade 3 in the US (Common Core 3.NBT.A.2), but use whatever level fits the child.

Tips

• Keep sessions short: one sheet of 10 to 20 questions a day beats a long session once a week.
• Mark the sheet together with the answer key and talk about the mistakes; each one shows what to practise next.
• Move to the next sheet when a child gets almost every question right without counting on fingers.
• Where it is offered, use the column layout for written methods and the across layout for mental strategies.

Worked example

356 + 478. Ones: 6 + 8 = 14, write 4 carry 1. Tens: 5 + 7 + 1 = 13, write 3 carry 1. Hundreds: 3 + 4 + 1 = 8. So 356 + 478 = 834. Check by estimating: about 350 + 480 = 830, which is close.

Common mistakes

Carrying into the wrong column or carrying twice. Say each step aloud: 'thirteen tens, write three, carry one hundred'.

Ignoring a carry out of the hundreds. If the hundreds add to 10 or more, the answer has four digits, as in 645 + 587 = 1232.

How to use this generator

Choose the options above the sheet: the number of questions and the settings for this kind of worksheet. Every change makes a new sheet straight away, and New worksheet gives a different set of questions with the same settings.

Each sheet has a worksheet number printed at the top. Type the same number later, or keep the page link, to print exactly the same questions and answer key again. Leave Answer key page ticked to print the answers on a second page, then press Print. Every printed page carries the makekite logo and web address.

Common questions

How can children check their answers?
Estimate first by rounding each number to the nearest hundred or ten. If the exact answer is far from the estimate, look for a missed carry.

How many questions should a child do?
Ten to twenty is plenty for daily practice. The 100-question drill sheet is for short timed practice once or twice a week.

Can I print the same worksheet again?
Yes. Note the worksheet number printed at the top, or keep the link in your browser's address bar, which ends with that number. Entering it later gives the same questions and answers.

Is it free?
Yes. There is no sign-up, and nothing you choose is sent anywhere: the sheets are made in your browser.