Primary 1 · Mathematics
P1 picture graphs
A P1 child can read a picture graph perfectly and still get the question wrong, because "how many more" sounds like adding. Two towers of Lego show why it is a comparison.
- Level
- P1
- Usually taught
- Term 2
- Covers
- 1 concept
What changes at P1
In Primary 1 your child reads picture graphs, where each picture stands for 1. They find which row has the most or the fewest, and how many there are altogether. They also find how many more or how many fewer one row has than another.
Reading the graph is the easy half. The marks go in the questions, where two of them use the same pair of rows in opposite ways. "Altogether" adds them; "how many more" compares them.
The sentence that costs the mark
The picture graph shows the books Aisha and Ben read last week. How many more books did Aisha read than Ben?
What the working usually does
add9 and 6=15
Reads both rows correctly, sees "more", and adds them.
What the question asked
difference of9 and 6=3
Compares the rows, so it takes the difference, 9 − 6.
Both numbers were read correctly and the sum is right, so the working looks fine. The only wrong decision is the operation, and it was made by one word in the question.
| Row | book |
|---|---|
| Aisha | 9 |
| Ben | 6 |
The same question, worked properly
Read the two rows
Aisha → 9, Ben → 6Write each row down as a number before doing anything with it. Each star stands for 1 book.
Decide what the question wants
how many more → compareThis is the step that fails. "How many more" compares the two rows, so it needs the difference. Adding them answers "how many altogether", a different question.
Find the difference
9 − 6 = 3Aisha read 3 more books. Check it on the graph: 3 stars in Aisha's row stand past the end of Ben's.
How can you tell it has clicked?
Ask two questions about the same graph: "how many altogether?" and then "how many more?". If both answers are 15, the word "more" is doing the deciding.
A child who checks the difference by pointing at the stars sticking out past the shorter row has understood what "how many more" asks. "How many fewer" is worth a try too, since it is the same subtraction with the opposite word.
One thing to try tonight
Build two Lego towers, one of 9 bricks and one of 6, and stand them side by side.
Ask "how many more bricks in the tall tower?". The answer is the part that sticks out, and it plainly is not 15 bricks tall.
What your child will meet in this topic
- Picture Graphs
Most Singapore schools introduce this in Term 2, 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
In P2, picture graphs get a key: one picture can stand for 2, 5 or 10. The same step still holds (compare, then subtract), with one multiplication added at the end.
The words themselves travel much further. "How many more", "fewer" and "the difference" all mean compare, and that decision sits under the comparison bar models of P2 and later years.
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.
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.