Step 5 Objective
Multiply and divide decimals mentally by 10 or 100, and integers by 1000, and explain the effect.
- Examples of what pupils should
know and be able to do - Probing questions
- What if pupils find
this a barrier?
Probing questions
Why do 25 ÷ 10 and 250 ÷ 100 give the same answer?
This calculator display shows 0.001. Tell me what will happen when I multiply by 100. What will the display show?
I divide a number by 10, and then divide the result by 10. The answer is 0.3.
What number did I start with? How do you know?
How would you explain to someone how to multiply a decimal by 10 . . . , how to divide a decimal by 100? . . .