Understanding that numbers can be decomposed by place value in more than one way lays the foundation for making sense of the regrouping necessary for using the standard algorithm for subtraction. When you regroup to solve 85 – 17, you are really decomposing 85 into 7 tens and 15 ones.
These cards are “puzzles” because they force students to decompose numbers in ways other than the traditional hundreds, tens, and ones. They are great for math workstations, but be sure to include base-ten blocks to support student understanding.
- 16 task cards with 2- and 3-digit numbers
- An interactive Google Slides file with the same task cards and movable base-10 pieces.
Includes both downloadable task cards as well as a digital version with movable base-ten blocks for use with Google Classroom™!