Understanding what kilo- (×1000), centi- (one hundredth), and milli- (one thousandth) mean when added to unit names.
Where your child meets this in real life: Understanding why a kilometre is longer than a metre, or why milligrams are tiny doses in medicine
Each SEAG paper has 28 maths questions. Questions 29 to 50 are multiple choice with five possible answers, and questions 51 to 56 need a short written answer. With 56 questions in 60 minutes across English and maths, that is about a minute per question.
SEAGReady breaks understand metric prefixes into 3 steps, taught in order so each skill builds on the last.
Understand that kilo- means 1000 times the unprefixed unit and apply it to the common kilometre/metre and kilogram/gram relationships
Understand that centi- means one hundredth of the unprefixed unit
Understand that milli- means 1/1000 of the unprefixed unit and distinguish it from centi-
Try three free questions from our understand metric prefixes course. They start easy and get harder, so you can see where your child's confidence runs out. If they manage the last one without a hint, this topic is probably secure. If not, the steps above show where to start.
Sean's cycling route is shown. How many metres is it?
The school-corridor measurement is shown. How long is it in metres?
Harry's wire-cutting information is shown. How many millimetres of wire are left?
This is the exact interactive worked example your child sees in SEAGReady. Step through it and watch the method build up.
Reece is training for a charity run. The route is 5 kilometres long.
How many metres is the route?
5 km = ? m
Kilo- means 1000 of the unprefixed unit
Step 1 of 3
Reece is training for a charity run. The route is 5 kilometres long.
How many metres is the route?
The route is 5000 metres long.
The key insight: Kilo- tells you the larger unit contains 1000 of the unprefixed unit!
Common mix-up: 5 km = 500 m. Kilo means ×1000, not ×100. There are 1000 metres in every kilometre.
These are the misconceptions we see most often in understand metric prefixes, including the ones our practice questions are specifically designed to catch.
Struggling with understand metric prefixes? The real gap is often in one of these earlier topics.
Sitting the SEAG test this November? Read our last-month revision plan, Paper 1 vs Paper 2 and test day guide.
SEAGReady finds the exact step where your child gets stuck, teaches it with worked examples like the one above, and brings it back for review so it sticks.
Free to start · no card needed