Recover Hidden Digits from Carries
In a partly blanked addition, subtraction, multiplication, or long division, the missing digits are deduced column by column from the lowest place up, using how carries and borrows must propagate. The same cryptarithm logic deepens from three-digit sums to multi-digit products and division. It trains airtight place-value bookkeeping.
grade 3–4 NBTOA Work BackwardsEliminate Possibilities
Progression (5)
3-1 1. Recover hidden digits using regrouping 3.NBT.A.23.OA.A.42.NBT.B.7
3-1 2. Recover missing digits from column carries 3.NBT.A.33.OA.B.5
3-2 3. Deduce missing digits in a multiplication 3.OA.C.73.NBT.A.3
3-2 4. Fill long-division blanks from the known 3.OA.C.73.OA.B.6
4-1 5. Deduce hidden digits from the ones place up 4.NBT.B.5