**
Basics
**• Decimals are based on the number ten.

• The basic units of the decimal system are 0 1 2 3 4 5 6 7 8 9 10.

• Many arithmetic problems produce an answer in decimal form.

• Zero is often used as a placeholder to the left of the decimal point —> 0.5 = .5

• There is an invisible decimal point to the right of any whole number —> 7. = 7

When asked to convert π, a fraction, or a square root to decimal form, use the toggle button .

is the decimal point command.

To convert a decimal to percent, move the decimal point two places to the right; this maneuver is the same as multiplying the decimal by 100.

0.07 → 7.% = 7%

0.07 × 100 = 7%

0.70 → 70.% = 70%

0.70 × 100 = 70%

To convert percent to a decimal, move the invisible decimal point two places to the left; this maneuver is the same as dividing the percent by 100.

0.07 ← 7.% = 7%

7 ÷ 100 = 0.07

0.70 ← 70.% = 70%

70 ÷ 100 = 0.70

The decimal system positions digits as wholes (tens, hundred, thousands, etc.) and parts (tenths, hundredths, thousandths, etc.) of ten.

**Positions**

2146.8

↑

thousands

2146.87

↑

hundreds

2146.873

”””↑

”””tens

2146.873

””””’↑

””””’ones

2146.873

””””””’↑

””””””’tenths

2146.873

””””””””↑

””””””””hundredths

2146.873

””””””””””↑

””””””””””thousandths

** **

**Question
**Convert 0.08 to percent.

**Answer
**8%

**Answer Process
**To convert a decimal to percent, move the decimal point two places to the right.

0.08 → 8.% = 8%

**
Question
**Convert 0.85 to percent.

**Answer
**85%

**Answer Process
**To convert a decimal to percent, move the decimal point two places to the right.

0.85 → 85.% = 85%

**
Question
**Convert 6% to a decimal.

**Answer
**0.06

**Answer Process
**To convert percent to a decimal, move the invisible decimal point two places to the left.

0.06 ← 6.% = 6%

**
Question
**Convert 65% to a decimal.

**Answer
**0.65

**Answer Process
**To convert percent to a decimal, move the invisible decimal point two places to the left.

0.65 ← 65.% = 65%

Question

What is 6.93 + 0.25?

**Answer**

7.18

Input |
Display |
Comment |

blinker | clears screen | |

6 93 + 0 25 | 6.93+0.25 | Addition |

7.18 | Answer | |

## Decimals |

Question

What is 6.93 – 0.25?

**Answer**

6.68

Input |
Display |
Comment |

blinker | clears screen | |

6 93 – 0 25 | 6.93-0.25 | Subtraction |

6.68 | Answer | |

## Decimals |

Question

What is 6.93 × 0.25?

**Answer**

1.7325

Input |
Display |
Comment |

blinker | clears screen | |

6 93 × 0 25 | 6.93*0.25 | Multiplication |

1.7325 | Answer | |

## Decimals |

Question

What is 6.93 ÷ 0.25?

**Answer**

27.72

Input |
Display |
Comment |

blinker | clears screen | |

6 93 ÷ 0 25 | 6.93÷0.25 | Division |

27.72 | Answer | |

## Decimals |

**
Question
**Round the previous answer to the nearest tenth.

**Answer**

27.7

**Answer Process**

See Rounding.

27.72 **→** 27.7

**
Practice – Questions
**1. Convert 9% to a decimal.

2. Convert 95% to a decimal.

3. Convert 0.04 to percent.

4. Convert 0.45 to percent.

5. Convert 0.455 to percent.

6. What is 3.94 + 0.33?

7. What is 3.94 – 0.33?

8. What is 3.94 × 0.33?

9. What is 3.94 ÷ 0.33?

10. With reference to Question 9, round your answer to the nearest hundredth.

**
Practice – Answers
**1. 0.09

2. 0.95

3. 4%

4. 45%

5. 45.5%

6. 4.27

7. 3.61

8. 1.3002

9. 11.93939394

10. 11.94