Reading Graphs and Tables: Where Children Misread Them

30 September 2026 · by Larry

A child looks at a bar graph of books borrowed, sees that the tallest bar reaches the line marked 20, and writes 20. The bars go up in fives and the tallest one ends a little above the 20, so the true reading is not 20. The child understood what a bar graph is and still lost the mark, because the scale was never read.

Graphs and tables look easy because there is almost no calculation. That is exactly why marks go here: the slips are in reading, and a child who rushes past the small print never gets to the part they are good at.

1. Not reading the scale

On a bar or line graph, the numbers along the side do not always go up in ones. They may go up in twos, fives, tens or hundreds, and the tick marks between the labelled numbers count too. The child has to work out what one small step is worth before reading anything.

Picture graphs have the same trap in a different form. A key at the bottom says one symbol stands for a number of items, and a half symbol stands for half of that. A child who counts five symbols and writes 5 has counted the pictures and skipped the key.

The habit: before answering anything, write the value of one step (or one symbol) beside the graph in pencil. It takes five seconds and every reading question depends on it.

2. Answering about the wrong bar, row or line

Read the question, then find the label. Children often glance at the tallest bar and answer, when the question asked about the second tallest, or about the month before. On a line graph with two lines, the key decides which line is which; reading the wrong line gives a neat, confident, wrong answer.

A cheap habit that helps: point at the exact bar, row or point with a finger or pencil tip, and only then read across to the scale. Reading across with nothing to follow lets the eye drift up or down.

3. “How many more” is a subtraction, and “altogether” is an addition

Once the numbers are read correctly, the question is a word problem in disguise, so the same slips show up. “How many more books were borrowed on Monday than on Friday?” asks for a difference. “How many books were borrowed on Monday and Friday?” asks for a total. A child who reads both bars correctly and adds when the question wanted the difference has done the graph part right and the question part wrong.

Ask the child to say in a full sentence what is being asked before touching a number: I need the difference between Monday and Friday. It is the same idea as in word problems where the sums are fine but the story is not, and it is why a graph question is not really a separate skill.

4. Tables: the total row and the empty cell

A table gives numbers in rows and columns, and some questions ask the child to complete it. Two slips are common. One is filling a cell from the wrong row, because the eye slid down a column. The other is trusting a total that is already printed and never checking that the parts add up to it. A finished table should agree with itself: the numbers in a row should add to that row’s total, and the column totals should add to the grand total. If they do not, something was read or copied wrongly.

That agreement is a free check. It costs a few seconds and catches a misread without redoing anything.

5. Line graphs: a value versus a trend

A line graph usually shows how something changes over time, such as temperature by hour or savings by month. There are two different kinds of question. One asks for the value at a certain point, which is a reading. The other asks whether something rose, fell or stayed the same between two points, which compares two readings. Children sometimes answer the second kind by pointing at the highest point on the whole graph. The question was about the stretch between two particular times, so only those two readings matter.

Also worth knowing: the line joins the points, but the values that were actually recorded are at the points. Read the point, not a spot somewhere along the line, unless the question says otherwise.

6. Pie charts: shares, not counts

A pie chart shows how a whole is divided. The slices together make the whole, which is the total number of things being shown, so a slice on its own is a share of the total rather than a number of items. A child who reads a big slice as a big number, with no total in sight, has answered a different question. If the question gives the total and a fraction or percentage for the slice, the answer is that fraction or percentage of the total, which is a fraction or percentage sum in its own right. Ratio and percentage, and where children slip covers that half.

7. No sense of whether the answer is sensible

A quick test before writing anything: could this answer come from this graph? If the tallest bar is nowhere near 100, an answer of 100 cannot be right. If a “how many more” answer is bigger than the bar it came from, something has gone wrong. Asking whether an answer is sensible is the same habit covered in careless mistakes in maths, and what they usually are.

A five-minute check at the kitchen table

Find a graph in a newspaper, a school worksheet or your child’s own assessment book, and cover the questions. Ask your child four things, in this order:

• What is this graph about? (The title and the labels on both sides.)
• What is one small step on the scale worth, or what does one symbol stand for?
• Point to one bar and tell me its value.
• Which is bigger, this one or that one, and by how much?

Where the answers stall shows which slip it is. If the value is off, it is the scale (slip 1). If the value is right but the wrong bar was chosen, it is the pointing habit (slip 2). If the values are right and the comparison goes wrong, it is a question-reading problem (slip 3), not a graph problem.

What helps

• Write the step value beside the graph. Every time, before any question.
• Point, then read. A finger or pencil on the exact bar, then across to the scale.
• Say what the question wants in a sentence before choosing add or subtract.
• Make one together. Tally the colours of cars outside your block, or the coins in a jar, then draw a bar graph with a scale you choose. Choosing a scale yourself makes other people’s scales easier to read.
• Check that the table agrees with itself. Rows add to row totals, columns to column totals.

What does not help

• Rushing through many graph questions for speed. Reading slips repeat faster, and they are habits, not knowledge gaps.
• Telling a child to “look properly”. It gives nothing to do. “Write the step value first” does.
• Treating every wrong answer as a maths weakness. Many of these children can do the sum without difficulty once the number has been read correctly.

Which kinds of graph your child is expected to handle depends on the level and on the school’s own workbook, so check what the class is on before spending long on any one type; the MOE primary mathematics syllabus on moe.gov.sg lists the topics by level. StudyLab’s games do not have a graphs topic, so this one is paper, a pencil and something to count. If the reading turns out to be fine and the arithmetic afterwards keeps slipping, averages, and where children slip covers a related topic where reading the data correctly comes first.