You are viewing a free preview of this lesson.
Subscribe to unlock all 10 lessons in this course and every other course on LearningBro.
This lesson covers DfE content statement L1.20 — converting between metric units of length, weight and capacity; working with time; and calculating with money.
The metric system is based on powers of 10, which makes converting between units straightforward. At Level 1 you need to convert between metric units only (not metric to imperial).
| Unit | Abbreviation | Relationship |
|---|---|---|
| Millimetre | mm | |
| Centimetre | cm | 1 cm = 10 mm |
| Metre | m | 1 m = 100 cm = 1,000 mm |
| Kilometre | km | 1 km = 1,000 m |
graph LR
km["km"] -->|"× 1,000"| m["m"]
m -->|"× 100"| cm["cm"]
cm -->|"× 10"| mm["mm"]
mm -->|"÷ 10"| cm
cm -->|"÷ 100"| m
m -->|"÷ 1,000"| km
| Unit | Abbreviation | Relationship |
|---|---|---|
| Gram | g | |
| Kilogram | kg | 1 kg = 1,000 g |
| Tonne | t | 1 t = 1,000 kg |
| Unit | Abbreviation | Relationship |
|---|---|---|
| Millilitre | ml | |
| Litre | l | 1 l = 1,000 ml |
| Conversion | How |
|---|---|
| cm → mm | × 10 |
| m → cm | × 100 |
| km → m | × 1,000 |
| kg → g | × 1,000 |
| l → ml | × 1,000 |
| mm → cm | ÷ 10 |
| cm → m | ÷ 100 |
| m → km | ÷ 1,000 |
| g → kg | ÷ 1,000 |
| ml → l | ÷ 1,000 |
Scenario: A door frame is 2.1 m tall. How tall is it in centimetres?
2.1 m × 100 = 210 cm
Scenario: A recipe needs 750 g of flour. How many kilograms is that?
750 g ÷ 1,000 = 0.75 kg
Scenario: A water tank holds 3.5 litres. How many millilitres is that?
3.5 l × 1,000 = 3,500 ml
Scenario: You buy 1.2 kg of apples and 450 g of grapes. What is the total weight in grams?
Step 1: Convert 1.2 kg to grams: 1.2 × 1,000 = 1,200 g Step 2: Add: 1,200 + 450 = 1,650 g
Exam Tip: Before adding or subtracting measurements, always convert to the same unit first. It does not matter which unit you choose, as long as they match. Then convert back to the unit the question asks for.
| Conversion | Value |
|---|---|
| 1 minute | 60 seconds |
| 1 hour | 60 minutes |
| 1 day | 24 hours |
| 1 week | 7 days |
| 1 year | 365 days (366 in a leap year) |
| 12-hour | 24-hour |
|---|---|
| 12:00 midnight | 00:00 |
| 6:30 am | 06:30 |
| 12:00 noon | 12:00 |
| 1:00 pm | 13:00 |
| 3:45 pm | 15:45 |
| 6:15 pm | 18:15 |
| 11:59 pm | 23:59 |
To convert from 12-hour to 24-hour: For pm times, add 12 to the hour. For am times, the hour stays the same (but write it with a leading zero if needed).
To convert from 24-hour to 12-hour: For hours 13-23, subtract 12 and add "pm". For hours 00-11, use the hour as is and add "am" (00 = 12 midnight).
Scenario: A bus leaves at 14:20. What is this in 12-hour clock?
14 − 12 = 2, so it is 2:20 pm
Scenario: A meeting starts at 10:45 am and finishes at 1:15 pm. How long does it last?
Method — count up in stages:
Scenario: A train departs at 09:48 and arrives at 11:23. How long is the journey?
Exam Tip: To find the length of time between two times, count up in stages rather than trying to subtract. Go to the next whole hour, then count the hours, then add the remaining minutes.
| Minutes | Hours and Minutes |
|---|---|
| 90 minutes | 1 hour 30 minutes |
| 135 minutes | 2 hours 15 minutes |
| 200 minutes | 3 hours 20 minutes |
To convert minutes to hours: Divide by 60. The whole number is the hours; the remainder is the minutes.
Subscribe to continue reading
Get full access to this lesson and all 10 lessons in this course.