Subtract 3-Digit Models (No Regrouping)
✂️ The Giant Demolition! We have to cross out Flats, Rods, and Cubes to find out what is left standing in the city.
Do this: Read the concept below, then try the quiz or activity.
Concept
Drawing the blocks is the perfect way to double check your test answers if you get confused.
🎯 The Triple Cross-Out Rule: Example: 356 - 124 = ? 1. Draw the start (356): 3 Flats, 5 Rods, 6 Cubes. 2. Attack the Cubes! (-4): Cross out 4 of the Cubes. (Leaves 2). 3. Attack the Rods! (-2): Cross out 2 Long Rods. (Leaves 3). 4. Attack the Flats! (-1): Cross out 1 Giant Flat. (Leaves 2). 5. Count the survivors: 2 Flats, 3 Rods, 2 Cubes. 6. Answer: 232!
Try it
Demolish the towers!
Instructions: Imagine the starting blocks. Cross out the exact number the bad guy tells you to cross out.
Problem 1: 458 - 213 = ? * Cubes: 8 - 3 = ___ cubes safe. * Rods: 5 - 1 = ___ rods safe. * Flats: 4 - 2 = ___ flats safe. * Answer: ___
Problem 2: 689 - 345 = ? * Answer: ___
Problem 3: You see a picture: 5 Flats, 4 Rods, 2 Cubes. The paper tells you to cross out 2 Flats, 1 Rod, and 0 Cubes (- 210). * Answer: ___
Problem 4: Subtract 102 from 834. * Answer: ___