Subtract Decimal Numbers using Partial Differences 5-101
Model and subtract ones, tenths, and hundredths using Base 10 discs and number bonds. What's 4.7 - 1.8? To get more tenths, shift 1 to get 3 ones and 17 tenths. Since 3 - 1 = 2 and 1.7 - .8 = .9, 4.7 - 1.8 = 2 + .9 = 2.9. Lay the foundation for vertical algorithms by regrouping and subtracting units that are the same.
