Decimals

decimal point


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 toggle .

decimal point 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.

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

Calculator Click What You See Comment
clear blinker clears screen
decimal point 93 + 0 decimal point 25 6.93+0.25 Addition
enter 7.18 Answer
Decimals


Question

What is 6.93 – 0.25?

Answer
6.68

Calculator Click What You See Comment
clear blinker clears screen
decimal point 93 – 0 decimal point 25 6.93-0.25 Subtraction
enter 6.68 Answer
Decimals


Question

What is 6.93 × 0.25?

Answer
1.7325

Calculator Click What You See Comment
clear blinker clears screen
decimal point 93 × 0 decimal point 25 6.93*0.25 Multiplication
enter 1.7325 Answer
Decimals


Question

What is 6.93 ÷ 0.25?

Answer
27.72

Calculator Click What You See Comment
clear blinker clears screen
decimal point 93 ÷ 0 decimal point 25 6.93÷0.25 Division
enter 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

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