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Subtract one part at a time
For 684,000 − 27,000, subtract 20,000, then 7,000. You get 664,000, then 657,000. The steps may be arranged differently, but the total removed must be 27,000.
Crossing a round number
In 705,030 − 8,000, subtract from 705 thousand, not just from the digit 5. The result is 697 thousand and 30, or 697,030. Changing a single digit is not enough when regrouping is needed.
If you subtract too much, add the excess back
For 452,300 − 9,900, subtract 10,000 and add back 100. You get 442,300 + 100 = 442,400. This is the reverse of addition compensation: here you removed too much.
Worked examples
705 030 − 8 000 = 697 030
Check: 697,030 + 8,000 = 705,030. The remainder 030 stays the same.
1 000 000 − 245 000 = 755 000
Subtract 200,000 to get 800,000, then subtract 45,000. Check that 755,000 + 245,000 equals one million.
Try it yourself
Your turn
Type the missing word, number, or sign. Spaces in large numbers are allowed. Try first, then open the explanation.
A game requires 900,000 points. A team has 674,000. How many more are needed? Check your answer.
See an example answer
900,000 − 674,000 = 226,000. Check: 674,000 + 226,000 = 900,000.
Check your knowledge
Choose one answer for each question. You can revise your answers and check again.
Answer key
- 480 000. 74 − 26 = 48 ten-thousands.
- 597 250. 601 thousand − 4 thousand = 597 thousand.
- Subtract 30,000, then add 100. You removed 100 too much, so add it back.
- 640 000. 640,000 + 360,000 = 1,000,000.
- 428 000 + 28 000 = 456 000. The difference plus the removed number recovers the starting number.