Time, money and using a calculator
Time
- 60 s = 1 min, 60 min = 1 h, 24 h = 1 day.
- The 24-hour clock uses four digits: 3.15 p.m. = 15 15.
- e.g. a film at 19 35 lasting 70 min (1 h 10 min) finishes at 20 45.
Practice
What is 3.15 p.m. on the 24-hour clock?
Add 12 hours to the afternoon time: 3.15 p.m. = 15 15.
Money & calculator
- Give money to 2 d.p. (4.8 → 4.80). Convert currency with the exchange rate as a multiplier.
- Rate 1 USD = 0.92 EUR: 150 USD = 138 EUR; 138 ÷ 0.92 = 150 USD.
- On a calculator, enter time as a decimal of an hour (2 h 30 min = 2.5, not 2.30); don't round mid-calculation.
Practice
The exchange rate is 1 USD = 0.92 EUR. How many euros is 150 USD?
150 × 0.92 = 138 EUR.
Practice
Entered as a decimal of an hour, what is 2 hours 30 minutes?
30 minutes is half an hour, so 2 h 30 min = 2.5 hours.
You've got it
Key idea
- 24-hour clock: 3.15 p.m. = 15 15; convert min↔h carefully
- money to 2 d.p.; convert currency with the exchange rate
- enter time as a decimal hour (2 h 30 min = 2.5)