# 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