Primary 1 · Mathematics
P1 multiplication and division
A table has 4 legs, so how many legs do 5 tables have? Many P1 children answer 9, and 5 plates of grapes show why the answer is 20.
- Level
- P1
- Usually taught
- Term 3
- Covers
- 1 concept
What changes at P1
Primary 1 meets multiplication and division before any times tables. Multiplication is equal groups: 5 groups of 4 is 4 + 4 + 4 + 4 + 4, written 5 × 4. Division means sharing equally, or putting into equal groups of a given size.
The times tables themselves come in P2. This year is about seeing the groups inside a story, which is the part the tables never teach.
The sentence that costs the mark
A table has 4 legs. How many legs do 5 tables have?
What the working usually does
5 +4=9
Finds the two numbers in the story and adds them.
What the question asked
5 groups of4=20
Sees 5 tables as 5 equal groups, with 4 legs in each.
Both numbers really are in the story, and 5 + 4 = 9 is a correct sum. Until now, every story with two numbers in it was an addition, so the habit has always been right before.
| Group | Detail |
|---|---|
| 20 |
The same question, worked properly
One table is one group
1 table = 4 legsStart with one table. Its 4 legs are one group of 4.
Five tables, five groups
5 groups of 4This is the step that fails. Each table brings its own 4 legs, so 5 tables are 5 equal groups of 4. They are not "5 and 4", which is how the story turns into 9.
Add the groups
4 + 4 + 4 + 4 + 4 = 20, so 5 × 4 = 20Add one group at a time: 4, 8, 12, 16, 20. There are 20 legs, and 5 × 4 is the short way of writing it.
How can you tell it has clicked?
Ask: a table has 4 legs, how many legs do 5 tables have? If the answer is 9, the two numbers were added because they were there.
Then ask your child to draw it first: 5 rings with 4 dots in each. A child who draws the groups before writing a sum has understood what multiplication is.
One thing to try tonight
Set out 5 plates and put 4 grapes on each. Ask how many grapes there are.
If the answer is 9, count them together a plate at a time: 4, 8, 12, 16, 20. The plates do the explaining, and the grapes can be eaten afterwards.
What your child will meet in this topic
- Multiplication and Division
Most Singapore schools introduce this in Term 3, though schools do differ by a term either way. If your child’s school runs a different order, you can set it in the schedule on your dashboard.
What it leads to
P2 builds the times tables on this, starting with 2, 5 and 10, then 3 and 4. A child who sees the groups can build a table; one who only recites it struggles to use it in a story.
Division starts here too, in its two meanings: sharing 16 stickers between 2 sisters, and putting 16 stickers into packs of 2. They look alike as sums and quite different as pictures.
The same topic in other years
It comes back each year and gets harder, so it helps to see what came before and what is coming.
More in Primary 1
Other topics in the same year, so you can see what sits either side of this one.
Struggling with the working rather than the topic itself? How to help your child with problem sums
See how your child is doing on this topic
StudyLah marks each step separately, so you can see whether it was the setup or the arithmetic that cost the mark.