Unit 3 Practice Converting
The ease of the metric system is that the conversion between, say milli- and kilo- is the same whether it is milimeters to kilometers or milligrams to kilograms (even though meters is for measuring length and grams is the unit of measure for mass).
Examples
1 km = 1000 m Example: 6.8 km = 6800 m (moved decimal 3 places to the right
1 kg = 1000 g Example: 2.4 kg = 2400 g (moved decimal 3 places to the right)
1000 mm = 1 m Example: 7400 mm = 7.4 m (moved decimal 3 places to the left)
1000 mg = 1 g Example: 4100 mg = 4.1 g (moved decimal 3 places to the left)
If you cannot remember which way to move the decimal point, but you do remember that 1 m = 1000 mm, and 1 km = 1000 m, you can set up ratios, then cross-multiply to convert. But since today’s lesson is only meters to millimeters (or the reverse), and kilometers to meters (or the reverse), we will be moving the decimal point 3 places, and only 3 places. We just need to figure out whether we move it to the left or to the right.
Are we going to a number that looks larger (but has the same value) because we moved the decimal to the right because of the smaller units used to measure; i.e., going from km to m or going from m to mm? Or are we going to a number that looks smaller (but has the same value) because we moved the decimal to the left because of the larger units used to measure, i.e., going from m to km or going from mm to m?
