Students will be able to subtract 100 from multiples of 100.
- Write the following numbers on the board: 100, 200, 300, 400, 500, 600, 700, 800, 900 and 1,000.
- Ask students what these numbers have in common.
- Explain that all of these numbers are multiples of 100. This means that 100 two times is 200, three times is 300, etc.
Explicit Instruction/Teacher modeling(10 minutes)
- Tell students that they are going to pretend to go shopping for some big items. They will have $1,000 and will be able to buy things with prices that are multiples of $100.
- On the board, draw several big-ticket items, such as a couch, trampoline, swing set, and TV. Write price tags showing prices that are multiples of $100.
- Tell students that you are going to decide what to buy with your $1,000.
- Pick one item and then subtract $1,000 – (cost of your item)To figure out how much money you have left.
Guided practise(5 minutes)
- Tell students that they should decide what other item you buy with the amount of money you have left.
- Have them turn to a partner to share what item they think you should buy, calculating how much money you would have left after buying it.
- Write number sentences on the board to represent the situations students describe.
Independent working time(20 minutes)
- Pass out paper to the students. Have them work in partners. Each partner should create a store of high-ticket items with prices that are multiples of $100. They should draw pictures and price tags for each item in their store.
- Tell the students they each have $1,000 and can pick as many items as they can afford to purchase from their partner’s store.
- The students should write number sentences to show how much money they have left after buying the items from the store.
Enrichment:Have students pretend to have $2,000 and do more shopping in their partners’ stores.
Support:Have students only buy one item from the partners’ stores, writing the corresponding number sentence.
- Assess student understanding by observing how they are subtracting by multiples of 100.
- Are they able to use their knowledge of place value to subtract quickly?
- Further assess their understanding by looking closely at how they write and solve number sentences.
Review and closing(5 minutes)
- Have students share the number sentences they created when shopping in their partners’ stores.