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Lesson · Grade 3 · Mathematics

Adding Three-Digit Numbers with Regrouping

  • Grade 3
  • Mathematics
  • 1 min 14 s
  • British Columbia
  • BC3-MA-07

The video works out 159 + 264 in columns, with base ten blocks beside the sum: ten ones snap into a ten and are carried to the tens, then ten tens snap into a hundred and are carried to the hundreds. The answer, 423, is checked by counting the blocks left (4 hundreds, 2 tens and 3 ones), and the video ends on the recap: ten ones make a ten, and ten tens make a hundred.

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In one sentence

The question this lesson answers

What is 159 plus 264?

Line up the hundreds, tens and ones.

Transcript

What the lesson says

What is 159 plus 264?

Line up the hundreds, tens and ones.

159 is 1 hundred, 5 tens and 9 ones.

264 is 2 hundreds, 6 tens and 4 ones.

Start with the ones: 9 plus 4 is 13.

Regroup: ten ones make one ten.

Write 3, and carry 1 ten to the tens column.

Now add the tens: 1 plus 5 plus 6 is 12.

Regroup: ten tens make one hundred.

Write 2, and carry 1 hundred to the hundreds column.

Add the hundreds: 1 plus 1 plus 2 is 4.

So 159 plus 264 is 423.

Check the blocks: 4 hundreds, 2 tens and 3 ones make 423.

Ten ones make a ten, and ten tens make a hundred.

Curriculum

Where this fits

British Columbia, Grade 3

Mathematics, Number: addition and subtraction to 1000BC3-MA-07

Previous: A Fraction of a GroupNext: Subtracting Three-Digit Numbers: Trade a Ten for Ten Ones

The outcomes and strands follow the British Columbia curriculum.

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