Addition with Regrouping centre
Students will be able to add by regrouping
- Call students to your group area.
- Set your cups up on three different levels using books or other props to create a mini staircase. Place a set of base 10 blocks on the table as well.
- Write "8+2" on the board with "8" on top and "2" on the bottom.
- Ask students what 8 plus 2 equals.
- When they say 10, write the zero under the 8 + 2 and 1 to the left in the invisible 10s spot.
- Next write a 1 in front of the 8 and change it to 18+2.
- Ask your students how they would think to solve this problem.
Explicit Instruction/Teacher modeling(15 minutes)
- Draw a line to separate the 1 and 8 to create a place value chart.
- Using the base 10 blocks, show students how you need one 10 block and eight 1 blocks to create 18. Place these blocks in the proper cups.
- Do the same for the 2.
- Next, show students how the 8 and 2 are in the ones column and the 1 is in the 10s column while labeling the columns above the written problem and the cups.
- Then, ask students what 8 plus 2 is.
- However, when they say 10, take the ones blocks from the cups and ask them to identify what happens when they have 10 ones.
- Remind students that they should group the ones and move them over to the 10s place. Pick up a 10s block and move it to the 10s spot and place it in the cup.
- Show them that they have no ones, because they became a 10. Write "zero" under the ones place on the written problems and write a one above the 10s column to show that added a group of 10.
- Now, ask how many 10s they have in the 10s cup.
- When they say 2, move the two 10s blocks to the 10s place equals cup and write the 2 under the 10s column of your written problem so it says 20.
- Point to the base 10 blocks count the number of ten blocks you have.
Guided practise(10 minutes)
- Repeat the steps in the explicit instruction a few times until the kids start to get the hang of it and are directing you what to do.
- Use numbers starting with 2-9 in the 10s spot for high level practise.
- Also practise with 3 and 3, 3 and 2, and 2 and 2 digit numbers not just the 2 and 1 digits in the example.
- The first few times, when they add the ones column, write the answer in the ones column and ask students if your answer is correct. If they do not think it is correct, ask them what you should do. Get them to tell you to regroup the 1s into 10s.
Independent working time(20 minutes)
- If you do maths centers or have individual place value sets, you can set this up in centers for your students to use.
- In the centre, have them use cards to decide which numbers will be where. Take out any double digit and K, Q, J, and Joker cards.
- Have students pull enough cards to make two two-digit numbers to add together.
- Have them sit the cups on top of the cards and put their base 10 blocks in the cups, then move them around as necessary to solve their problem.
- Enrichment:Challenge students by adding more place values for students to add.
- Support:Work with struggling students one-on-one or in a small group. These students may also need assistance in understanding how the base 10 blocks are to be used.
- Hand out the Addition with Carrying worksheet for students to complete individually.
- Check worksheets for correctness.
Review and closing(5 minutes)
- Call students back to the carpet for a few more rounds of practise as a class. Make up problems on the board or come up with short word problems to introduce them to the concept.