Interactive guide
Column Arithmetic Restoration
JuniorMathsPuzzles: Column Arithmetic Restoration
Restore a Column Addition
Step 1 / 35
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8
4
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Damaged record
Asterisks are missing digits. The layout still tells us the place values.
How it worksRead guide
A damaged arithmetic record is a column calculation where some digits have been replaced by \*.
The puzzle is not just to guess the hidden digits. Use the column structure:
- work from the units column first;
- keep track of carries and borrows;
- remember that a multiplication partial product is shifted one place to the left for the tens digit;
- check the completed record from top to bottom.
Start with short additions, then move on to subtraction and multiplication with partial products.
Problems
Restore a compact additionL1Restore the additionL1Restore the multiplicationL1Restore an addition with carryingL2Restore the subtractionL2Restore a two-digit multiplicationL3Restore the hidden multiplierL3Restore a multiplication with an 8 tens digitL4Restore the shifted partial productsL4Restore a harder multiplicationL5Restore a three-by-eight multiplicationL5Restore a three-partial multiplicationL5Restore a multiplication with a middle 3L6Restore a multiplication with sixes in the partialsL6