0580
Time, Currency and Conversions
Number
Conversions to know
- Time does not use the decimal system, so its conversions have to be learned rather than derived
| Unit | Equals |
|---|---|
| 1 minute | 60 seconds |
| 1 hour | 60 minutes |
| 1 day | 24 hours |
| 1 week | 7 days |
| 1 year | 12 months, taken as 365 days |
- This specification treats a year as 365 days unless a question states otherwise
- Month lengths are needed for date calculations: April, June, September and November have 30 days, February has 28 (29 in a leap year), and the remaining seven have 31
Minutes are not decimals of an hour
- Sixty minutes make an hour, so a part-hour written as a decimal is a fraction of 60, not of 100
- 15 minutes is 0.25 h, 30 minutes is 0.5 h, and 45 minutes is 0.75 h
- Writing 2 hours 30 minutes as 2.30 hours is wrong; it is 2.5 hours