What is the breaking-apart (decomposition) strategy for addition?

Split one number into place-value chunks and add them on one at a time.

47 + 38 → keep 47, split 38 into 30 + 8 → 47 + 30 = 77 → 77 + 8 = 85.

Check: 47 + 38 = 85. ✓ It works because addition is associative — you're free to regroup the pieces. Split whichever number makes the running total land on easy stepping stones (here, 77 then 85).