Symbols and the key
A pictogram shows how many there are of each thing by drawing small pictures called symbols. Each row is one kind of thing. This pictogram shows fruit in a bowl, so count the symbols in each row: 4 apples, 6 pears and 3 plums.
Under the rows is the key. It shows one symbol and says what that symbol stands for. Here the key says each symbol stands for 1, so every symbol is one piece of fruit.
The key says each symbol stands for 1: there are 4 apples, 6 pears and 3 plums.
The longest row
Every symbol is drawn the same size, so the longest row has the most symbols. The pears row is the longest, so there are more pears than apples or plums. The plums row is the shortest, so there are fewest plums.
To find how many more pears there are than plums, subtract: 6 − 3 = 3. There are 3 more pears than plums.
Read the key first
A symbol does not always stand for 1. In this pictogram the key says each symbol stands for 2. The apples row has 3 symbols, and each one is 2 apples, so there are 2 + 2 + 2 = 6 apples, not 3.
Count the symbols first, then multiply by the key. The pears row has 5 symbols, and 5 × 2 = 10 pears. The plums row has 2 symbols, and 2 × 2 = 4 plums.
The key says each symbol stands for 2. The pears row has 5 symbols: 5 × 2 = 10 pears.
A bigger key, a shorter row
A key bigger than 1 saves drawing. 30 pears would need 30 symbols if each stood for 1. With a key of 5, they need only 6 symbols, and the row is read by counting in fives, once for each symbol: 5, 10, 15, 20, 25, 30.
The same picture can stand for different amounts, because the key decides what one symbol is worth. That is why the key is read before anything else.
The same rows with a key of 5: 4 × 5 = 20 apples, 6 × 5 = 30 pears and 3 × 5 = 15 plums.
6 symbols × 1 = 6: the symbols stay the same, and the key says what each one is worth
Pick the key that makes the pears row 30
The rows keep the same symbols whatever the key. Each row total is the number of symbols times the key.
Symbols are not the answer
The usual mistake is to give the number of symbols as the answer. With a key of 2, a row of 3 symbols is 6, not 3. The same goes for "how many more": in the pictogram with a key of 2, the pears row has 5 − 2 = 3 more symbols than the plums row, and 3 symbols stand for 3 × 2 = 6 more pears.
Worked example: Each Picture Stands for 2: A Row of 6 Pictures
Question A pictogram shows the favorite toys of some children. Each picture stands for 2 children. The Car row has 6 pictures. The Doll row has 4 pictures. The Ball row has 3 pictures. (a) How many children chose the car? (b) How many children chose the car or the doll altogether?
1.Look at the key first. Each picture stands for 2 children, so count in 2s and say one number for each picture.
Look at the key first. Each picture stands for 2 children. 2.The Car row has 6 pictures. Count 2, 4, 6, 8, 10, 12.
The Car row has 6 pictures. Count in 2s, once for each picture: 2, 4, 6, 8, 10, 12. 3.(a) 12 children chose the car.
(a) 12 children chose the car. 4.The Doll row has 4 pictures. Count 2, 4, 6, 8. So 8 children chose the doll.
The Doll row has 4 pictures: 2, 4, 6, 8. So 8 children chose the doll. 5.(b) Add the two rows: 12 + 8 = 20 children.
(b) 12 + 8 = 20 children chose the car or the doll.
Answer: (a) 12 children; (b) 20 children
Common mistakes
- Writing 6 children for the Car row because the row has 6 pictures. The key says each picture stands for 2 children, so 6 pictures stand for 12 children.
- Adding the pictures for part (b) and writing 6 + 4 = 10 children. 10 is the number of pictures. Each picture stands for 2 children, so 10 pictures stand for 20 children.
Worked example: How Many More: Compare the Pictures First, Then Use the Key
Question A pictogram shows the sports that some children chose. Each picture stands for 2 children. The Swim row has 7 pictures. The Run row has 4 pictures. The Dance row has 5 pictures. (a) How many more pictures are in the Swim row than in the Run row? (b) How many more children chose swimming than running?
1.Look at the Swim row and the Run row. The Swim row has 7 pictures and the Run row has 4 pictures.
The Swim row has 7 pictures and the Run row has 4 pictures. 2.(a) 7 − 4 = 3. The Swim row has 3 more pictures than the Run row.
(a) 7 − 4 = 3. The Swim row has 3 more pictures than the Run row. 3.Each picture stands for 2 children, so the 3 extra pictures stand for 2 + 2 + 2 = 6 children.
Each picture stands for 2 children, so the 3 extra pictures stand for 2 + 2 + 2 = 6 children. 4.(b) 6 more children chose swimming. Check: the Swim row is 14 children and the Run row is 8 children, and 14 − 8 = 6.
(b) 6 more children chose swimming. Check: 14 − 8 = 6.
Answer: (a) 3 more pictures; (b) 6 more children
Common mistakes
- Writing 3 more children for part (b). 3 is the number of extra pictures. Each picture stands for 2 children, so 3 extra pictures stand for 6 children.
- Comparing the Swim row with the Dance row because the Dance row is next to it. The question names the Run row, so compare 7 pictures with 4 pictures.