Recently we’ve been looking at arrays to help us better understand multiplication. Today we’re going to write as many different number sentences as we can using only numbers from the following set: 3, 4, 5, 12, 15, 20 (e.g. 3 × 4 = 12 and 12 ÷ 4 = 3).
First, group all the number sentences from the same family together. For example, here are eight number sentences from one fact family (there are two more fact families possible with the numbers provided):
Now, it’s your turn to see how many you can create with the remaining numbers.
Below is a list of all the missing number sentences associated with the three by four array. The first column contains the fact family, while the number sentences in the other columns have a missing number. In your maths book, complete the equations with the missing number filled in.
You’ll be given a set of 6 cards to use with a partner. This task requires you to:
- Shuffle each set, face down.
- Deal a red card, a blue card, a red card, a blue card and a red card along the table.
- Turn over and read the number sentence, for example 3 ÷ 12 = 4. (If there is no = in the number sentence, deal again).
- Write this ‘fact’ down under either the heading TRUE or the heading FALSE. In this case, it goes under FALSE
- Discuss why this is the case.
- Pick up all the cards, shuffle, and play again.
- Place the resulting fact under the appropriate heading e.g. 3 = 12 ÷ 4 goes under the heading TRUE.
- Continue making the list
Swap with the other students at your table and repeat this activity.
Once finished, you can collect a ‘Fact family wheel of fortune’ sheet from Angela. Stick it in your book once you’re done and then you can go to: