Worked examples
Two examples
Example 1
A bag of rice has a mass of 2.5 kilograms. How many grams is that?
- Before you calculate, ask one question: is the new unit bigger or smaller than the old one?
- Grams are smaller than kilograms. You need more of a small unit to make the same amount, so the number must get bigger: multiply.
- There are 1,000 grams in a kilogram (kilo- means 1,000). 2.5 × 1,000 = 2,500.
- Check: the number got bigger, as it should.
Answer: 2,500 grams
Example 2
A bottle holds 350 milliliters. How many liters is that?
- Is the new unit bigger or smaller? Liters are bigger than milliliters.
- You need fewer of a big unit, so the number must get smaller: divide.
- There are 1,000 milliliters in a liter (milli- means one thousandth). 350 ÷ 1,000 = 0.35. Dividing by 1,000 moves the decimal point three places to the left.
- Check: a liter is a large bottle, and 350 mL is about a third of one, so 0.35 makes sense.
Answer: 0.35 liter
Where this is taught: Science Practices, part 6: Numbers and units in science · Look Again Quiz 6: Numbers in Science
In your Kaplan book: Unit 4, Chapter 1, Lesson 6: Apply Scientific Formulas · Map of the Terrain, topic 6: Numbers in science
The drill
Ten questions
How many:
Read what is in the box first, if there is one. Then tap your answer; a few questions ask you to choose words from a drop-down instead, the way the GED test does. Press Check my answers at the bottom.Read what is in the box first, if there is one. Circle your answer; where there are brackets, circle the choice that fits. The answer key, with the reasoning, is on the last page.