Written multiplication can be done step-by-step by setting out the calculation carefully and remembering to regroup if necessary.
78 × 7
1. Rewrite the calculation vertically, like this:
2. Then multiply the numbers in the ones column together, so 8 × 7 = 56.
Write the 6 in the ones column and regroup the 5 tens below in the tens column.
3. Next multiply the numbers in the tens column together, so 7 × 7 = 49 and add the 5 that was regrouped.
This gives us 49 + 5 = 54, so we write the 4 in the tens column and the 5 in the hundreds column.
So 78 × 7 = 546
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