11 Plus Measurement Units: Length, Weight, Capacity & Time

Length: Metric and Imperial Conversions

Length questions in the 11 Plus focus primarily on metric units: millimetres, centimetres, metres, and kilometres. Your child must know the conversion factors: 10 millimetres in a centimetre, 100 centimetres in a metre, and 1,000 metres in a kilometre. These conversions must be instant, any hesitation slows down every calculation that follows.

The most common question types are straightforward conversions (convert 3.5 metres to centimetres), comparison problems (which is longer: 250 cm or 2.4 m?), and word problems that require converting between units within a multi-step calculation. Comparison questions are particularly common because they test whether children can convert to a common unit before comparing.

Imperial units occasionally appear, though less frequently than metric. Your child should know that there are 12 inches in a foot, 3 feet in a yard, and 1,760 yards in a mile. Some tests also include approximate metric-imperial equivalents: one inch is approximately 2.5 centimetres, one mile is approximately 1.6 kilometres, and one foot is approximately 30 centimetres.

A common error is confusing the direction of conversion. When converting from a larger unit to a smaller one (metres to centimetres), multiply. When converting from a smaller unit to a larger one (centimetres to metres), divide. Teaching your child to check whether the answer should be a bigger or smaller number than the starting value catches many errors before they are written down.

Practise length conversions daily using quick-fire questions: how many centimetres in 4.7 metres? How many kilometres in 3,500 metres? How many millimetres in 12.3 centimetres? Speed and accuracy in these conversions is the foundation for tackling more complex measurement problems.

Weight and Capacity: Grams, Kilograms, Litres

Weight and capacity follow the same metric structure as length and use the same conversion principles. For weight, your child must know: 1,000 grams in a kilogram, and 1,000 kilograms in a tonne. For capacity, the key facts are: 1,000 millilitres in a litre.

Weight questions commonly involve cooking or shopping contexts: a recipe requires 750 grams of flour, and you have a 2 kilogram bag, how much is left after making the recipe? These word problems require conversion followed by subtraction, and the real-world context helps make them accessible.

Capacity questions often involve filling containers, dividing liquids, or comparing volumes. For example: a jug holds 1.5 litres. How many 250 ml glasses can be filled from the jug? This requires converting litres to millilitres and then dividing.

Imperial weight and capacity units appear less frequently but are worth knowing. Pounds and ounces (16 ounces in a pound) and pints and gallons (8 pints in a gallon) occasionally feature. Approximate metric-imperial equivalents include: one kilogram is approximately 2.2 pounds, and one litre is approximately 1.75 pints.

The same error-checking strategy applies here: when converting to a smaller unit, the number should get bigger; when converting to a larger unit, the number should get smaller. If the answer goes in the wrong direction, the operation (multiply or divide) has been confused.

EdifyPod Nexus includes measurement conversion in its adaptive maths practice, ensuring your child encounters these question types regularly. Eddy identifies whether conversion knowledge, arithmetic, or reading comprehension is the stumbling block and targets practice accordingly.

Time Calculations and the 24-Hour Clock

Time questions are among the trickiest measurement problems because time does not follow the decimal system. There are 60 seconds in a minute, 60 minutes in an hour, and 24 hours in a day. Children who try to use standard addition and subtraction with time values without adjusting for the base-60 system make frequent errors.

The most common time question types are: converting between 12-hour and 24-hour clock formats, calculating the duration between two times, adding or subtracting intervals to find start or end times, and multi-step problems involving timetables or schedules.

For 12-hour to 24-hour conversion, children need to know that times from 1:00 PM onwards add 12 to the hour. So 3:30 PM becomes 15:30, and 11:45 PM becomes 23:45. Converting back, subtract 12 from hours greater than 12. Midnight is 00:00 and noon is 12:00.

For duration calculations, the counting-on method is most reliable. To find the time between 09:45 and 14:20, count: 09:45 to 10:00 is 15 minutes, 10:00 to 14:00 is 4 hours, 14:00 to 14:20 is 20 minutes. Total: 4 hours 35 minutes. This method avoids the errors that occur when children try to subtract directly.

Other time facts to memorise include: 7 days in a week, approximately 30 or 31 days in a month (with February having 28 or 29), 52 weeks in a year, and 365 or 366 days in a year. Leap year knowledge occasionally appears in questions.

Practise time questions regularly because the non-decimal system catches out even confident mathematicians. Include real-life practice: calculating journey times, working out how long until an event, and reading timetables.

Practice Strategy for Measurement Mastery

Building measurement fluency requires a combination of memorising conversion facts, practising conversions until they are automatic, and applying these skills in word problem contexts. Here is a practical approach.

First, create a reference sheet listing all the conversion facts your child needs to know. Include metric conversions (mm to cm, cm to m, m to km, g to kg, ml to l), imperial conversions (inches to feet, feet to yards, yards to miles, ounces to pounds, pints to gallons), and approximate metric-imperial equivalents. Test your child on these facts regularly until they can recall every one instantly.

Second, practise conversions daily using quick-fire exercises. Present ten conversion questions and time your child. Aim for all ten correct in under two minutes. Mix the question types so your child cannot predict which conversion will come next.

Third, practise word problems that require measurement conversions as part of a multi-step solution. These problems test whether your child can identify that a conversion is needed, perform it correctly, and then use the result in the broader calculation. Include problems from all four measurement areas: length, weight, capacity, and time.

Fourth, use real-world opportunities to practise measurement. Cooking involves weight and capacity naturally. Planning journeys involves time and distance. Shopping involves weight and price. These practical contexts reinforce the mathematics and build the familiarity with measurement that examiners look for.

EdifyPod Nexus integrates measurement practice into its maths curriculum, with Eddy adapting the focus based on your child's performance. For families who want additional targeted support, edifypod.com/11plus offers Group and 1-to-1 Tutoring that includes measurement as a core topic.

Finally, review errors carefully. Measurement mistakes often fall into predictable categories: wrong conversion factor, wrong operation (multiplying instead of dividing or vice versa), or arithmetic errors during the conversion. Identifying the specific error type allows you to target practice precisely.