Activities to Teach Students to Use Models to Subtract Two-Digit Numbers – With Regrouping
When students are learning how to subtract two-digit numbers, they may become overwhelmed with the number of steps involved in the process. Using models can help students visualize and understand the concept of regrouping, which is a crucial skill for subtracting numbers that require borrowing. Here are some activities that can help teach students how to use models to subtract two-digit numbers with regrouping.
1. Base Ten Blocks:
Base ten blocks are manipulatives that students can use to represent numbers using units, rods, flats, and cubes. You can give each student a set of base ten blocks to represent the two-digit numbers they are subtracting. Ask students to show the problem using base ten blocks, and then guide them through the process of regrouping by instructing them to trade ten units for a rod, ten rods for a flat, and so on.
2. Number Charts:
Number charts are a useful tool for helping students visualize the relationship between numbers. Have students use a number chart to subtract two-digit numbers. For example, if the problem is 47 – 23, they would start at 47 and count back 23 spaces on the chart. This activity can help students see how subtraction involves counting backwards and how regrouping changes the number being subtracted.
3. Place Value Mats:
Place value mats are another helpful tool for understanding how regrouping works. You can make place value mats by drawing larger versions of the place value chart on poster board or using dry erase boards. Students can represent the two-digit numbers using place value cards and then use the mats to subtract by regrouping. This activity can help students see how regrouping affects both the ones and tens places.
4. Vertical Subtraction with Models:
Once students have a firm grasp of the concept of regrouping, they can move on to vertical subtraction problems. Give students a worksheet with vertical subtraction problems and ask them to use models to help them solve the problems. For example, if the problem is 54 – 28, they would use base ten blocks or a place value mat to represent the numbers and then carry out the subtraction algorithm. This activity can help students see how models can be used to support the traditional algorithm for subtracting two-digit numbers.
By using these activities, you can help students understand how regrouping works when subtracting two-digit numbers. These models can help students visualize the process and gain a deeper understanding of the concepts behind subtraction. By using models, students can feel confident and successful as they practice subtracting two-digit numbers with regrouping.