lesson
Keep every place aligned
1 · Learn
Column methods scale to larger numbers when equal places remain aligned. Start with the ones and record each exchange.
For 48,765 + 27,586, the total is 76,351. An estimate of about 50,000 + 30,000 = 80,000 helps detect a gross error, but does not prove the exact sum.
2 · Worked example
I subtract 27,586 from 76,351 to recover 48,765. For a mental calculation such as 48,765 − 2,000, I remove two thousands directly.
3 · Your turn
Calculate 62,408 − 18,759. Check by addition.
Check your answer
43,649; 43,649 + 18,759 = 62,408.
4 · Apply your learning
Model one exchange in the subtraction with place values, then compare a formal method with an estimate.
Adult guidance and safety
Model the calculation or measurement before relying on a procedure. Explain estimates, units and checks. Use a ruler/protractor and suitable diagrams where needed; text examples alone do not establish practical skill or fluency.
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Check a calculation · Year 5 onward
Use this only when your teacher or adult allows a calculator for the task. Show your thinking first. It does not replace mental or written arithmetic and does not mark your lesson answer.
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