Time Currency And Conversions

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Notes

Time Conversions

1 $day = 24$ hours, 1 hour $= 60$ minutes, 1 minute $= 60$ seconds.
To convert days to hours, multiply by 24 (e.g., 3 days $= 72 hours)$ .
To convert hours to minutes, multiply by 60; minutes to seconds, multiply by 60.
For reverse conversions, divide by the appropriate factor.

12-Hour and 24-Hour Clocks

12-hour clock uses AM (midnight to midday) and PM (midday to midnight).
24-hour clock runs from 00:00 (midnight) to 23:59; no AM/PM needed.
To convert 12-hour PM to 24-hour, add 12 to the hour $(e.g., 3:25pm = 15:25)$ .
$12:00am = 00:00, 12:00pm = 12:00$ .

Calculating with Time

Work in chunks: add minutes to next hour, then whole hours, then remaining minutes.
When crossing AM/PM, remember that 12:00pm is midday and 12:00am is midnight.
For time intervals, subtract start from end, using chunking or conversion to minutes.
Example: 07:35 to 08:14 is 25 $min + 14$ $min = 39$ min.

Bus and Train Timetables

Timetables typically use 24-hour clock; times are four digits without colon.
Each column represents a different service; times are usually departure times.
To find journey duration, subtract departure time from arrival time for the same service.
Example: 0800 at Coronation Street to 0840 at Ramsey Street $= 40$ minutes.

Time Zones

Time zones differ by hours; some locations are ahead, others behind.
To convert, add or subtract the time difference depending on direction.
If a location is behind, subtract hours; if ahead, add hours.
Example: Madrid is 7 hours ahead of Chicago; 17:15 Madrid $= 10:15$ Chicago.

Exchange Rates

Exchange rate shows how much one currency is worth in another.
To convert from currency A to B, multiply amount in A by the rate (A to B).
To convert from B to A, divide amount in B by the rate (A to B).
Example: $1 $= 0.8626$ euros; $650 $\times 0.8626 =$ €560.69.

Converting Units of Length, Mass, Capacity

Length: 1 $cm = 10$ mm, $1 m = 100$ cm, 1 $km = 1000 m$ .
Mass: $1 g = 1000$ mg, 1 $kg = 1000 g, 1$ tonne $= 1000$ kg.
Capacity: 1 litre $= 1000$ ml, 1 $ml = 1 cm^{3}$ .
To convert, multiply or divide by powers of 10; e.g., 5.3 $km = 5300 m$ .

Squared and Cubic Units

For area, square the linear conversion: $1 m^{2} = 100$ $cm \times 100$ $cm = 10 000 cm^{2}$ .
For volume, cube the linear conversion: $1 m^{3} = 100$ $cm \times 100$ $cm \times 100$ $cm = 1 000 000 cm^{3}$ .
$1 cm^{2} = 100 mm^{2}, 1 km^{2} = 1 000 000 m^{2}$ .
$1 cm^{3} = 1000 mm^{3}, 1 km^{3} = 1 000 000 000 m^{3}$ .

Time Conversion Chart

24-Hour Clock Conversion

Currency Conversion Diagram

Squared and Cubic Unit Conversion

Practice questions

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1.How many hours are there in 3 days?
Easy
- A36 hours
- B48 hours
- C72 hours
- D24 hours
2.Change 5.3 kilometres into metres.
Easy
- A530 m
- B5300 m
- C53 m
- D0.53 m
3.Write 3.25 pm in the 24-hour clock.
Easy
- A03:25
- B15:25
- C13:25
- D3:25
4.Change 4.6 metres to centimetres.
Easy
- A460 cm
- B46 cm
- C0.046 cm
- D4600 cm
5.Change 560 metres into kilometres.
Easy
- A5.6 km
- B0.56 km
- C56 km
- D560000 km
6.Change 3670 centimetres to metres.
Easy
- A36.7 m
- B367 m
- C3.67 m
- D0.367 m
7.Change 4365 metres into centimetres.
Easy
- A43.65 cm
- B436500 cm
- C436.5 cm
- D4.365 cm
8.Change 645 mm into cm.
Easy
- A6.45 cm
- B64.5 cm
- C6450 cm
- D0.645 cm

Summary

## Time, Currency & Conversions – Quick Revision ### Time - **Conversions**: 1 min = 60 s, 1 h = 60 min, 1 day = 24 h, 1 week = 7 days, 1 year = 365 days. - **12-hour vs 24-hour**: 12:00 am = 00:00, 12:00 pm = 12:00. Add 12 for pm (except 12 pm stays 12:00). - **Calculating durations**: Work in chunks – minutes to next hour, then whole hours, then remaining minutes. - **Time zones**: If behind, subtract hours; if ahead, add hours. ### Exchange Rates - **Convert**: Multiply when going to the currency on the right of the rate; divide when going to the left. - E.g., £1 = €1.17: £ → € multiply by 1.17; € → £ divide by 1.17. - **Check**: If result should be bigger or smaller than original. ### Converting Units - **Length**: 1 cm = 10 mm, 1 m = 100 cm, 1 km = 1000 m. - **Mass**: 1 g = 1000 mg, 1 kg = 1000 g, 1 tonne = 1000 kg. - **Capacity**: 1 litre = 1000 ml, 1 ml = 1 cm³. - **Area**: Square the conversion factor. 1 cm² = 100 mm², 1 m² = 10 000 cm², 1 km² = 1 000 000 m². - **Volume**: Cube the conversion factor. 1 cm³ = 1000 mm³, 1 m³ = 1 000 000 cm³. ### Tips - For time, use calculator's ° ' '' button if needed. - When stuck on multiply/divide, test both and pick the sensible one.

Key terms

24-hour clock: Time format using four digits (00:00 to 23:59). Midnight is 00:00, midday is 12:00.
12-hour clock: Time format using am (midnight to midday) and pm (midday to midnight).
Exchange rate: The value of one currency in terms of another, e.g., £1 = €1.17.
Conversion factor: The number used to multiply or divide when converting units (e.g., 100 cm per metre).
Squared units: Area units obtained by squaring the linear conversion factor (e.g., 1 m² = 10 000 cm²).
Cubic units: Volume units obtained by cubing the linear conversion factor (e.g., 1 m³ = 1 000 000 cm³).

Slides

Time Conversions

1 minute $= 60$ seconds, 1 hour $= 60$ minutes, 1 $day = 24$ hours, 1 week $= 7$ days, 1 year $= 365$ days.
Time does not use the decimal system; be careful when calculating durations.
To find the number of hours in 3 days, multiply 3 by $24 = 72$ hours.

How many hours are in 3 days?

72 hours
36 hours
48 hours
60 hours

12-hour and 24-hour Clock

12-hour clock uses am (midnight to midday) and pm (midday to midnight).
24-hour clock uses four digits: first two for hour (00-23), last two for minutes (00-59).
Examples: 3.25 $pm = 15:25, 12:00$ $am = 00:00, 12:00$ $pm = 12:00$ .

Write 3.25 pm in the 24-hour clock: ____.

Calculating with Time

Work in chunks: add minutes to next hour, then whole hours, then remaining minutes.
For example, a film starts at 15:35 and lasts 1 hour 45 minutes: $15:35 + 1$ hour $= 16:35, +25$ min to 17:00, +20 $min = 17:20$ .
Be careful with am/pm boundaries when using 12-hour clock.

A lesson starts at 11:05 and lasts 75 minutes. What time does it end?

12:20
12:30
12:15
12:25

Exchange Rates

Exchange rate tells how much one currency is worth in another.
To convert from currency A to B, multiply by the rate (if rate is $1 A = x B)$ .
To convert from B to A, divide by the rate.
Example: $1 $= 0.8626$ euros, so $650 $= 650 \times 0.8626 = 560.69$ euros.

Ivy changes $650 into euros. Exchange rate: $1 $= 0.8626$ euros. She receives ____ euros.

Converting Units of Length

1 $cm = 10$ mm, $1 m = 100$ cm, 1 $km = 1000 m$ .
To convert from larger to smaller, multiply; from smaller to larger, divide.
Example: 5.3 $km = 5.3 \times 1000 = 5300 m$ .

Change 5.3 kilometres into metres.

530 m
5300 m
53 m
53000 m

Converting Units of Mass and Capacity

$1 g = 1000$ mg, 1 $kg = 1000 g, 1$ tonne $= 1000$ kg.
1 litre $= 1000$ ml, 1 $ml = 1 cm^{3}$ .
Example: 4.37 litres $= 4.37 \times 1000 = 4370 cm^{3}$ .

Change 4.37 litres into cubic centimetres: $____ cm^{3}$ .

Squared and Cubic Units

For area, square the conversion factor: $1 m^{2} = 100$ $cm \times 100$ $cm = 10 000 cm^{2}$ .
For volume, cube the conversion factor: $1 m^{3} = 100$ $cm \times 100$ $cm \times 100$ $cm = 1 000 000 cm^{3}$ .
Example: $2.54 m^{3} = 2.54 \times 1 000 000 = 2 540 000 cm^{3}$ .

Convert $2.54 m^{3}$ to $cm^{3}$ .

$2540 cm^{3}$
$25400 cm^{3}$
$254000 cm^{3}$
$2540000 cm^{3}$

Time Zones

Different countries have different time zones; some are ahead, some behind.
To convert, add or subtract the time difference.
Example: Buenos Aires is 5 hours behind Madrid. A flight leaves Madrid at 20:55 and arrives 03:50 local time (Buenos Aires). Flight time $= 7$ hours 55 minutes.

Diego flies from Madrid (20:55) to Buenos Aires (arrives 03:50 local). Buenos Aires is 5 hours behind Madrid. How long is the flight?

6 h 55 min
7 h 55 min
8 h 55 min
7 h 5 min

Using Timetables

Bus and train timetables usually use 24-hour clock.
Each column is a different service; times are departure times except last stop which is arrival.
To find journey time, subtract departure time from arrival time for the same service.

Which of these are true about timetables?

Timetables often use 24-hour clock.
Each column represents a different bus or train.
The time in each cell is the arrival time at that stop.

Review: Key Conversions

Time: 1 $day = 24$ hours, 1 hour $= 60$ minutes, 1 minute $= 60$ seconds.
Length: 1 $cm = 10$ mm, $1 m = 100$ cm, 1 $km = 1000 m$ .
Currency: Multiply when converting to a currency that is worth less per unit, divide when converting to a currency that is worth more.

Rashid changes 30 000 rupees to dollars. Exchange rate: $1 $= 68.14$ rupees. How many dollars does he receive?

$440.27
$440.00
$441.00
$439.50

Flashcards

How many hours are in 3 days?

72 hours.

Convert 5.3 kilometres to metres.

5300 m.

Convert 4.6 metres to centimetres.

460 cm.

Convert 560 metres to kilometres.

0.56 km.

Convert 3670 centimetres to metres.

36.7 m.

Convert 4365 metres to centimetres.

436500 cm.

Convert 645 mm to cm.

64.5 cm.

Write 3.25 pm in the 24-hour clock.

15:25.

A bus leaves at 0735. Sami takes 23 minutes to walk to the bus station. What is the latest time he can leave his house?

07:12 (or 7:12 am).

A bus journey takes 41 minutes, departing at 0735. What is the arrival time?

08:16.

Thor changes 40 000 Icelandic Krona into dollars at 1 krona = $0.0099. How many dollars does he receive?

$396.

Jeremy buys a bracelet for 2050 yen at 1 $yen =$ $0.0125. Calculate the price in dollars, correct to the nearest dollar.

$26.

A lesson starts at 1105 and lasts 75 minutes. What time does it end?

12:20.

Ivy changes $650 into euros at $1 $= 0.8626$ euros. How many euros does she receive?

560.69 euros.

Convert 4.37 litres to cubic centimetres.

$4370 cm^{3}$ .

Sean buys a pot costing 1200 yuan at $1 $= 6.4$ yuan. Cost in dollars?

$187.50.

Café opening times: Mon-Fri 8am-6pm, Sat 9:30am-3pm, Sun closed. Total hours open per week?

55.5 hours.

A train from Woodton to Northley takes 6h 25m, leaves at 19:46. Arrival time?

02:11 (next day).

What is 7 hours 36 minutes before 13:26?

05:50.

Levante changes 24 650 Hungarian forints to dollars at $1 $= 290$ forints. How many dollars?

$85.

Rashid changes 30 000 rupees to dollars at $1 $= 68.14$ rupees. How many dollars?

$440.27 (approx).

Musa has a 250ml glass, drinks 5 glasses from a 2-litre bottle. Water left in ml?

750 ml.

Peter works Mon 08:30-16:00, Tue 10:00-17:00, Thu 08:30-16:30, Sat 08:00-18:30. Total hours per week?

31 hours.

A machine paints 80 m in 5 minutes. How many metres in 45 minutes?

720 m.

How many minutes to paint a 2.8 km line at 80 m per 5 minutes?

175 minutes.

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