Recall the number of 10s within decades and decades that add to 100.

Recall groupings within 100.

Find out how many ones, tens, hundreds and thousands are in all of a whole number.

Know what happens when a number is multiplied or divided by a power of 10.

Number Framework Stages 4-8

Calculators

The students work in pairs. One student begins by putting a number into the calculator, for example, 67. Then an instruction is given. “Zap out the 6 in 67”. Here 67 – 60 “zaps” the 6. The students “zap“ by using numbers and the +, – , _, or ÷ buttons. The students should also demonstrate the process that the numbers go through with arrow cards. For example, 67 on arrow cards becomes 7 by removing the card that shows 60.

Repeat for: 45 to 75, 56 to 50, 40 to 100, 66 to 23 ...

#### Activity

Increase the difficulty of the examples to match the abilities of the students by increasing the whole number size, using decimal cards, and getting the students to zap two or more digits simultaneously.

Examples: 5 678 to 5 168, 4 444 to 4 114, 5 678 to 5 600, 678 to 621, 1.32 to 1.29, 3.427 to 3.024 ...

#### Extension Activity

Use many different operation buttons to convert a number to another given number. For example, when 20 is in the display, it could be converted to 40 by:

+ 20, ÷ 0.5, or + 100%, or x 2!, _ 2, – -20 ...

Examples: 15 to 30, 0.5 to 2, 100 to 10, 1 000 to 1, 0.56 to 560 ...