Tally charts and pictograms
Maths · Key Stage 1 · The School
Tallies: why the fifth one lies down
A tally chart records things as they happen. Four upright marks, then the fifth drawn across them as a gate: that group of five is what makes a long list countable. Counting in fives to 30 is quick; counting 30 separate marks is slow and easy to lose. Try tallying the colour of every car that passes for five minutes and you will feel why.
Pictograms and the key
A pictogram uses a picture for each thing counted — but check the KEY first. If one apple picture stands for 2 apples, then three pictures mean 6, not 3. Half a picture means half of whatever the key says. Reading the key before the pictures is the single habit that prevents nearly every pictogram mistake.
Asking the chart questions
A chart is for answering questions, not decorating a page. WHICH IS MOST? Find the tallest bar or longest row. HOW MANY ALTOGETHER? Add every category. HOW MANY MORE? Subtract the smaller from the larger — this is the one children skip, because "how many more" sounds like adding. Say it as "what is the difference" and the subtraction becomes obvious.
A pictogram of favourite fruits shows apples with 4 whole pictures, bananas with 2 pictures and a half. The key says one picture = 5 children. Apples: 4 × 5 = 20 children. Bananas: 2 × 5 = 10, plus half a picture = 2 or 3, so about 12. How many MORE chose apples? 20 − 12 = 8. Read without the key you would have said 4 and 2 and a difference of 2 — wrong three times over, from one skipped step.