A Peek Beyond the Point
Units of measurement
See how decimals make it easy to change between units of measurement.
Our units of measurement go in 10s, 100s and 1000s, so changing units is just moving the decimal point: count the zeros.
Length
| Fact | So |
|---|---|
| 1 cm = 10 mm | 1 mm = 0.1 cm; 5 mm = 0.5 cm; 12 mm = 1.2 cm; 5.6 cm = 56 mm |
| 1 m = 100 cm | 1 cm = 0.01 m; 10 cm = 0.1 m; 15 cm = 0.15 m |
| 1 m = 1000 mm | 1 mm = 0.001 m |
Decimals let us talk about tiny things: a human hair is about 0.1 mm thick; a newspaper sheet 0.05 to 0.08 mm; a mustard seed 1 to 2 mm. The smallest ant found so far, *Carabera Bruni (Sri Lanka and China), is 0.8 to 1 mm long. The smallest land snail, Acmella Nana* (Malaysia), has a shell just 0.7 mm across!
Weight: 1 kg = 1000 g, so 1 g = 0.001 kg; 5 g = 0.005 kg; 10 g = 0.010 kg; 254 g = 0.254 kg (2 tenths, 5 hundredths, 4 thousandths). And 1 g = 1000 mg, so 1 mg = 0.001 g.
Money: ₹1 = 100 paise, so 1 paisa = ₹0.01, and 75 paise = ₹0.75. There used to be coins of 1, 2, 3, 5, 10, 20, 25 and 50 paise; all coins of 25 paise and less were withdrawn in 2011, though paise still appear in bills and bank statements. In the 1970s a masala dosa cost 50 paise, a banana 20–25 paise, and a kilo of rice ₹2.45!
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