Add and Subtract Decimals and Multiply and Divide Decimals | Six Minutes: Grade 5 Math, Part 9

Six Minutes: Grade 5 Math, Part 9: Add and Subtract Decimals and Multiply and Divide Decimals: Line up the points, then add or subtract (5.NBT.7); then Multiply and Divide Decimals Adding and subtracting decimals to hundredths comes down to one rule: line up the decimal points so ones meet ones and hundredths meet hundredths. Grid models show why, and regrouping works exactly as it does for whole numbers. Then: Multiply decimals to hundredths with area models and the count-the-decimal-places method, and divide by shifting both numbers until the divisor is whole. Every answer is checked a second way, and the add-versus-multiply decimal point rule is cleared up. Chapters 0:00 Introduction 0:22 Line up the dots 0:45 See it with a grid 1:22 Worked example 2:56 Trap 3:17 Recap 3:41 See it with a grid 4:22 Count decimal places 4:46 Dividing decimals 5:12 Worked example 5:57 Trap 6:19 Recap 6:38 Thanks for watching Practice problems 1. A water bottle holds 1.75 liters and a jug holds 2.4 liters. How much water do they hold together? Answer: 4.15 liters (1.75 + 2.40 = 4.15; check: 1 + 2 = 3 and 0.75 + 0.40 = 1.15, and 3 + 1.15 = 4.15). 2. A rope is 6.5 meters long. A piece measuring 2.85 meters is cut off. How much rope is left? Answer: 3.65 meters (6.50 - 2.85 = 3.65; check: 3.65 + 2.85 = 6.50). 3. A tile is 0.8 meters by 0.6 meters. Find its area two ways (area model and whole-number method). Answer: 0.48 square meters. 4. How many 0.4-liter cups fill a 2.8-liter jug? Check by multiplying back. Answer: 7 cups, since 7 × 0.4 = 2.8. Six Minutes @SixMinuteClass: One technique, about six minutes. The narrator's voice is synthetic (computer-generated). Independent educational video. © 2026 Six Minutes · @SixMinuteClass