Measurement questions in Edutest maths

Numbers in real units: length, mass, capacity, area, volume and time. Measurement has its own place in Edutest's description of Mathematics: year-level maths: numbers, measurement, algebra, space and data.

Our questions are written for children in Years 6–7 applying for Year 7 or 8. At that level, your child converts between metric units and finds the perimeter and area of rectangles and shapes made from them. They also find the volume of boxes and link cubic centimetres to millilitres.

Time is part of it too: 12- and 24-hour time, durations, timetables and calendars. Around Year 7, areas of triangles and parallelograms join the list.

The seven in the table below, known without thinking. Expect a conversion inside a measurement question, so a quick one frees your child to focus on the problem itself.

Going to a smaller unit makes the number bigger, and going to a larger unit makes it smaller. If an answer moves the wrong way, a conversion went backwards.

Area and volume conversions are the hard ones. A square metre is 100 cm by 100 cm, so it holds 10 000 square centimetres, not 100.

Choose one unit first, then name what is being measured. The arithmetic in our questions is light, so these two steps are where the marks are won or lost.

We wrote these four in the Edutest style, from easier to harder. Each one shows the answer and the working. Read them with your child and name the unit each one works in.

Ask which option looked right at first, then look for the unit change it missed. Rewriting each amount in the chosen unit shows which step went wrong.

Count up in hops, never subtract times like decimals. Time runs in sixties and twenty-fours, and months differ in length, so column sums from school give answers that look right and aren't.

For durations, count up to the next whole hour, then whole hours, then the rest.

For calendars, add up the days between the dates and divide by seven. Whole weeks land on the same weekday, and the remainder says how far to move on. The knuckle method for month lengths is worth teaching, because treating a long month as a short one shifts the weekday.

Each trap below is a unit or a shape idea used the wrong way. When your child falls for one, name it, then use its fix on the next few measurement questions.

• Writing 9 kg 600 g as 9.06 kg. 600 g is 0.6 kg, because there are 1000 g in a kilogram.
• Dividing a volume by an edge. A 2 cm cube has a volume of 8 cm³, not 2. Counting cubes along each edge avoids this.
• Assuming water keeps its depth. When water is poured into another tank, the volume stays the same and the depth changes with the base area.
• Same perimeter, same area. It isn't so: a 9 by 5 rectangle and a 7 by 7 square have the same perimeter but different areas.

Because rulers stay at home: Edutest doesn't allow calculators, rulers, dictionaries, working-out paper, mobile phones, smart watches and fitness trackers. Every length has to come from the numbers in the question.

Treat any diagram as a sketch, not a drawing to measure. If a length isn't given, look for a way to work it out from the ones that are, often by adding or subtracting the sides of a rectangle.

Cooking and shopping are easy practice. Read a mass in grams and say it in kilograms, work out how many 250 mL cups fill a 2 L jug, or time a trip and find how long it took.

Measurement leans on decimals and multiplication, so the fractions page helps here too, and area questions overlap with geometry.

In the app, the measurement lesson has an Interactive version and Notes. There are also drills by section and topic; a free account drills the free test's questions, and a paid plan opens the rest.

Four questions show the method; the Mathematics section of Practice test 1 shows whether your child can use it against the clock. Afterwards, results by skill show whether measurement is the area costing marks.