Working with numbers
Multiplication and division
In this unit you multiply by putting equal groups together, and you divide by sharing into equal groups. Arrays help you see the groups clearly.
Equal groups and repeated addition
When things come in equal groups, you can add the groups to find how many. Three groups of 5 is 5 + 5 + 5 = 15. Adding the same number again and again is called repeated addition.
Multiplication
Multiplication is a quick way to add equal groups. Three groups of 5 is written as 5 × 3 = 15. You can multiply in either order: 2 × 4 = 4 × 2 = 8.
Arrays
An array shows equal groups set out in neat rows, like a muffin tray. An array with 2 rows of 6 shows 2 × 6 = 12. Arrays help you count equal groups and see multiplication.
Counting in 2s, 5s and 10s
Counting in equal steps helps you learn the tables for 2, 5 and 10. Count in twos: 2, 4, 6, 8, 10. Count in fives: 5, 10, 15, 20, 25. Count in tens: 10, 20, 30.
Division as sharing and grouping
Division shares a whole into equal groups, or makes equal groups from a whole. Share 6 buns onto 2 plates: 6 ÷ 2 = 3 on each plate. Or put 6 buns into groups of 2: that makes 3 groups. Both are 6 ÷ 2 = 3.
Worked examples
Add equal groups
- There are three groups of 5.
- Add them: 5 + 5 + 5.
- 5 + 5 + 5 = 15.
Answer: 5 + 5 + 5 = 15
Multiply with an array
- The array has 2 rows with 6 in each row.
- That is 2 groups of 6.
- 2 × 6 = 12.
Answer: 2 × 6 = 12
Count in fives
- Start at 0 and count in fives.
- 5, 10, 15, 20, 25, 30, 35.
- The 7th number you say is 35.
Answer: The 7th number is 35.
Divide by sharing
- There are 6 buns and 2 plates.
- Put one bun on each plate, again and again, until none are left.
- Each plate has 3 buns.
Answer: 6 ÷ 2 = 3
Where you see this in real life
- Working out how many cakes are on a tray by counting the rows in an array.
- Sharing 30 strawberries equally between 5 children.
- Making teams of 5 from a class of 30 children.
Key words
- Multiply
- To find how many there are in equal groups all together.
- Repeated addition
- Adding the same number again and again, like 5 + 5 + 5.
- Array
- Equal groups set out in rows, used to show multiplication.
- Equal groups
- Groups that all have the same number in them.
- Divide
- To share a whole into equal groups, or make equal groups from a whole.
- Double
- Two of the same number added together, like double 5 is 10.