Double Trouble: Subtraction Practice
Students will be able to accurately subtract two-digit problems with regrouping.
- Gather students together in a circle. On a small whiteboard, write the subtraction problem 31 – 16, vertically. Say, "I have 31 delicious cupcakes. I give 16 away to my friends. How many do I have left?" Explain to the students that to solve this problem, we can use base-ten blocks.
- Get out base-ten blocks. Have a student create the total number of cupcakes and place the blocks on the place value chart.
- Say, "I want to take 16 cupcakes away. Hmm. I see that I can take one group of ten, which is equal to ten ones. But I only have one 1 in my ones place! What should I do?"
Explicit Instruction/Teacher modeling(5 minutes)
- Allow a few students to offer ideas. Next, explain to the students that regrouping in subtraction means borrowing value from a higher place value. Show students how to exchange one group of ten for ten ones. Place the ten ones on the place value chart in the correct column.
- Model how to take 16 away. Ask students to count the remaining blocks.
- Say, "By regrouping my blocks, I was able to figure out that I only have 15 cupcakes left!"
- Ask students to do a think-pair-share to explain the strategy of regrouping.
Guided Practice(20 minutes)
- Pass out the game sheets for Math-Go-Round and the necessary materials.
- Review the rules on the game sheets with the students.
- Model playing the game with a student volunteer.
- Put students in partnerships and monitor the students as they play, providing support as needed.
Independent working time(15 minutes)
- Hand out the In the Jungle: Subtraction Practice worksheet to each student.
- Have students complete the worksheet independently, providing access to manipulatives to support students in using various strategies.
Enrichment: Assign a game sheet at a more challenging level.
Support: Write problems in a place value chart for students. Give students manipulatives to help them see physical evidence of subtraction.
- Collect the worksheets and use them as a formative assessment to check student understanding of subtracting two-digit numbers with regrouping.
Review and closing(5 minutes)
- Have a discussion with your students. Potential guiding questions include:
- What does it mean to regroup?
- When would you need to regroup? How do you know?
- Instruct your students to create illustrations on the board to help them in their explanations.