Number Chart Boogie
Students will be able to subtract multiples of ten.
- Show students a 100 chart.
- Point to the number 77. Ask, “How could I use the chart to find ten less than 77?”
- Show students that ten less than 77 is 67. The number directly above a number on a 100 chart is 10 less.
Explicit Instruction/Teacher modeling(10 minutes)
- Tell students that you are now going to find out what 40 less than 77 is.
- Ask, “How many tens is 40?” Explain that you will have to subtract four tens from 77.
- Starting with 77 on the 100 chart, move up four vertical spots. Say, “77-40=37.”
- Write the number sentence 77-40=37 on the board. Explain how four tens were subtracted from the 7 tens in 77.
- Tell students that they are going to work on subtracting multiples of tens. Multiples of ten are numbers that are made with multiple tens. They will be working with multiples under 100: 10, 20, 30, 40, 50, 60, 70, 80, and 90.
Guided practise(10 minutes)
- Hand out copies of number charts to the students (one per pair).
- Tell them to work in pairs to play “Number Chart Boogie.” In this game, students take turns telling their partner a number to start with and a multiple of ten to subtract from that number.
- Have partners take turns giving each other numbers to subtract.
Independent working time(15 minutes)
- Pass out the Number Chart Mystery worksheets.
- Have students work independently to solve the mystery.
Enrichment:Have students create their own mysteries for other students to decode. Ask them to model their work on the Number Chart Mystery worksheet.
Support:Have students work in partners to complete the Number Chart Mystery worksheet.
Assess students’ understanding by observing how they are subtracting by ten. Are they able to use the number chart to subtract quickly? Further assess their understanding by looking closely at their work on the Number Chart Mystery worksheet.
Review and closing(5 minutes)
Have students share their answers to the Number Chart Mystery and any additional mysteries that were completed for enrichment.