Add And Subtract Decimals
Adding and subtracting decimals is the almost the same as adding and subtracting whole numbers.
Be careful...
- Line up the decimal point and the columns
- Fill in any blank decimal places with zeros.
Example One - Addition
What is the sum of 3.45 and 67.8? (Line up the columns. Fill in any blank decimal places with zeros.)
Answer:
| 3.45 |
| + 67.80 |
| 71.25 |
Example Two - Subtraction
What is the difference between 67.8 and 3.45? (Line up the columns. Fill in any blank decimal places with zeros.)
Answer:
| 67.80 |
| – 3.45 |
| 64.35 |
Question - Novelty Contact Lenses
At c-r-a-z-y-e-y-e store, I bought 3 pairs of novelty contact lenses - Cats Eye for $58.95, Rainbow Eye for $38.78, and Green Dragon for $29.55. How much change did I receive from $150 cash?
Answer
$22.72 to nearest cent; $22.70 cash
Question - Feeler Gauge
A feeler gauge is a tool used by engineers and car mechanics for measuring gap widths such as the gap in a spark plug. The six gauges have widths of 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm and 0.6 mm. Which combination of these would be used to measure a gap of 1.5 mm?
Answer
0.4 mm + 0.5 mm + 0.6 mm = 1.5 mm
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