Number Knowledge 9 – Twos, fives and tens multiplication
- Recall multiplication facts for 2s, 5s and 10s.
- Recall groupings of two in numbers to 20, groupings of five in numbers to 50, and groupings of ten in numbers to 100.
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Teacher notes
- Students beginning level 2 should be encouraged to use addition facts rather than skip counting strategies for facts they cannot recall.
- When students have developed an understanding of multiplication they should begin to learn the x 2, x 5 and x 10 facts until they can confidently recall them. When students also understand the commutative property of multiplication, this halves the number of facts they need to learn.
- The game Spin bingo on page 120 of the student book can be used for the x 5 and x 10 tables. The cards for these are included in Number Knowledge 9 - Game - Spin Bingo (10 pages).
Number Knowledge 10 – Multiplying by 10 and 100
- Know that when a number is multiplied by 10 or 100 all the digits move one (for 10) and two (for 100) places to the left on a place value chart.
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Teacher notes
- It is extremely important to discourage students from saying that when you multiply by 10 you “add a zero”, or when you multiply by 100 you “add two zeros”, because this thinking confuses students later when they work with decimals and this rule no longer applies.
Instead, stress the importance of understanding that the value of each digit in the number becomes tens times larger when the number is multiplied by 10 and so moves one place to the left on a place value chart. In the same way, the value of each digit becomes 100 times larger when a number is multiplied by 100.
