Measurement and Data
Pictographs and bar graphs
Record data with tallies, read pictographs and bar graphs where one unit stands for many, and answer questions from them.
Data is easier to think about once it is drawn. A tally chart is the quickest way to record it as it arrives — one line per item, with every fifth line struck across the other four so that the marks can be counted in fives. A pictograph and a bar graph then turn those counts into a picture you can compare at a glance.
Have a play
Every line across this graph is worth 5 books. Look at how far up each bar reaches and work out what it is worth.
Tap any part of the picture.
Always read the key first
A pictograph rarely draws one symbol per item — that would take for ever. Instead a key says what one symbol is worth: 1 symbol = 10 cars. A bar graph does the same job with its scale, where one square up the side might be 4 children. Reading either without checking the key first is how a chart gets misread by a factor of ten.
Have a play
Move the bars up and down, and watch the number each one stands for.
Worked example
A pictograph uses 1 symbol for every 10 cars. One row has 3 and a half symbols. How many cars is that?
Three whole symbols stand for 3 × 10 = 30 cars.
The key turns symbols into cars by multiplying.
Try it together
Now let us read a pictograph where one symbol stands for 20 books.
Two rows: the first has 4 symbols, the second has 6. Turn each row into books, then compare them.
1.The first row has 4 symbols. How many books is that?
Have a go
Have a go on your own: one symbol stands for 6 marbles. How many marbles do 5 symbols show?
Hint: Five sixes.
Ready to practice?
Eight questions on what you have just read. Nothing is timed, and you can play as many times as you like.