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Lesson · Grade 5 · Mathematics

Subtracting Big Numbers: Regrouping Across Zeros

  • Grade 5
  • Mathematics
  • 1 min 38 s
  • British Columbia
  • BC5-MA-11

To work out 400 003 − 156 278, we go left past four zeros to the 4 and trade 1 hundred thousand for 10 ten thousands, then each 10 passes 1 along and becomes 9 until the ones become 13. Every column can then be subtracted, giving 243 725, and adding 243 725 + 156 278 = 400 003 checks the answer.

Concept: Subtracting big numbers with regrouping

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In one sentence

The question this lesson answers

What is 400,003 minus 156,278?

Write them in place value columns, with the ones lined up.

Transcript

What the lesson says

What is 400,003 minus 156,278?

Write them in place value columns, with the ones lined up.

Start with the ones: 3 is less than 8, so we need to regroup.

The next four places are all 0, so keep going left to the 4.

Trade 1 hundred thousand for 10 ten thousands.

Each 10 gives 1 to the place on its right and becomes 9.

The last 10 gives 1 to the ones, so the 3 becomes 13.

Now subtract, starting with the ones: 13 minus 8 is 5.

Tens: 9 minus 7 is 2.

Hundreds: 9 minus 2 is 7.

Thousands: 9 minus 6 is 3.

Ten thousands: 9 minus 5 is 4.

Hundred thousands: 3 minus 1 is 2.

So 400,003 minus 156,278 is 243,725.

Check by adding: 243,725 plus 156,278 is 400,003.

With zeros in the way, go left past them, and each 0 becomes 9.

Curriculum

Where this fits

British Columbia, Grade 5

Mathematics, Number: addition and subtraction of whole numbers to 1 000 000BC5-MA-11

Previous: Adding Big Numbers with RegroupingNext: Friendly Numbers: Adding by Compensating

The outcomes and strands follow the British Columbia curriculum.

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