In this activity, students draw on their knowledge of factors and known multiplication and division facts to determine which whole numbers are divisible by 2, 4, 5 or 10.
Knowledge of place value and number properties such as divisibility can equip students to carry out a range of computations mentally.
Students use knowledge of multiplication and division facts to determine which numbers are divisible by various factors.
Pose the scenario:
Someone said that if you know what a number is divisible by, you can solve a lot of division problems in your head.
I have 20 biscuits to pack with 5 biscuits in each box. How many boxes will I need?
- Will this divide equally?
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How did you decide?
Note whether students used their knowledge of multiplication facts (i.e. 4 \(\times\) 5 = 20, so 20 ÷ 5 = 4).
- What other numbers will divide into 20 equally?
- How did you decide?
List student responses and the reasons given (e.g. "2 will work because 2 tens is 20 and 20 is an even number so it will divide equally by 2")
You will need a 1–100 chart and the multiplication fact grid.
Your students can get extra practice using the learning object L2006 The divider: with and without remainder.
