Split it into rectangles: area
The Short Answer
Area is the space inside a shape, measured in square units. For a rectangle it is length times width. For anything made of right angles, cut it into rectangles, find each area, and add them — and the sides you need for that are usually the ones the diagram has not labelled.
What is an area question?
The space inside a shape. For a rectangle, length times width — which your child has known since Year 3.
What the 11+ does is stop giving them rectangles.
Split it into rectangles
Any shape made of right angles can be cut into rectangles, and once it is, the question becomes two easy multiplications and an addition.
Draw the split line on the diagram. Not in your head. A drawn line makes both rectangles' dimensions visible; an imagined one leaves your child holding four numbers and guessing which belongs to which.
Sometimes subtract instead
When a shape looks like a rectangle with a bite taken out of it, going the other way is quicker.
That same L is a 15 × 10 rectangle with a 6 × 4 corner removed. So: 150 − 24 = 126.
Which is a different shape from the one above, and the point stands — read the diagram, decide whether adding or subtracting suits it, and say which you are doing before you start.
Why the unit is squared
Because area counts squares.
A 3 cm by 4 cm rectangle holds twelve little squares, each one centimetre across. So the answer is twelve square centimetres.
Say that once and the squared unit stops being a rule to remember and becomes a description of what was counted.
Where do pupils lose marks?
Answering in centimetres rather than square centimetres.
Using an unlabelled side without working it out first.
Splitting badly — into shapes that are not rectangles, which cannot be calculated.
Adding when the diagram invited subtracting, which is slower rather than wrong.
Try it yourself
Draw the split line on the diagram before calculating. Then find each rectangle separately.
- A rectangle is 12 cm by 7 cm. What is its area?
- An L-shape splits into a 9 cm by 10 cm rectangle and a 6 cm by 4 cm rectangle. What is its area?
- Could that L-shape be split a different way?
- A 15 cm by 10 cm rectangle has a 6 cm by 4 cm corner removed. What is the area left?
- Why must the answer be in square centimetres?
- 84 cm². Twelve times seven, and the unit is square centimetres because we are measuring the space inside.
- 114 cm². 9 × 10 = 90, and 6 × 4 = 24, and 90 + 24 = 114.
- Yes — the same L can be cut vertically instead of horizontally, giving two different rectangles. The two areas will differ, and their total will still be 114. That is a useful check: split it the other way and see whether you get the same answer.
- 126 cm². The whole rectangle is 15 × 10 = 150, and the removed corner is 6 × 4 = 24, so 150 − 24 = 126. Subtracting is often quicker than adding when a shape looks like a rectangle with a bite out of it.
- Because area counts squares. A shape 12 cm by 7 cm holds 84 squares each measuring one centimetre by one centimetre — so the answer is 84 square centimetres, not 84 centimetres.
How much practice does this type need at home?
Squared paper and a pencil. Draw an L-shape, ask your child to find its area, and then ask them to find it a second way — the other split, or by subtraction.
Getting the same answer twice by two routes teaches something a correct answer on its own does not: that the method is a choice, and that the shape does not care which one they pick.
Free: a Maths workbook
Questions across the Maths question types, with the method printed at the top and full answers at the back. One workbook for the whole strand, not a sheet per question type.
Frequently Asked Questions
How does my child decide where to split a compound shape?
Anywhere that produces rectangles, and it genuinely does not matter which way. Most L-shapes can be cut horizontally or vertically, and both give the right answer. Encourage drawing the line on the diagram rather than imagining it, because a drawn line makes the two rectangles' dimensions obvious and an imagined one does not.
When is subtracting better than adding?
When the shape looks like a full rectangle with a piece missing. A 15 by 10 rectangle with a 6 by 4 corner removed is quicker as 150 − 24 than as two rectangles added. Both work; teaching both means your child can pick whichever suits the diagram, which is usually obvious once they know they have a choice.
Why do children give area answers in centimetres?
Because that is the unit printed on the diagram. Area is not a length, though — it counts squares, so the unit is square centimetres. It is worth saying once that a 3 cm by 4 cm rectangle contains twelve little squares, each a centimetre across, because after that the squared unit stops being a rule and becomes a description.
How is this different from the perimeter question?
Same shapes, opposite question. Perimeter travels round the edge and the answer is in centimetres; area covers the inside and the answer is in square centimetres. The first thing to do on either is underline which word the question used, since the diagrams look identical.
Sources
- GL Assessment — 11+ familiarisation materials and question type descriptions Published 2025.
- Clever Clogs Academy — our own Year 4 and Year 5 lesson records, Winslow Published September 2025 to July 2026.
We are not affiliated with, endorsed by or connected to GL Assessment or Buckinghamshire Council. Test arrangements change; always check the council's own pages for the current year's dates.
We Teach This Method Every Week in Winslow
Groups of no more than six pupils with two qualified teachers, in person or online. Come and see a session before you decide.