Rounding Decimal Numbers

1
(No Transcript)
2
(No Transcript)
3
(No Transcript)
4
(No Transcript)
5
(No Transcript)
6
(No Transcript)
7
(No Transcript)
8
(No Transcript)
9
Rounding Decimal Numbers

• Locate the digit in the place you are rounding to
  (called the rounding digit).
• Look at the digit to the right of the rounding
  digit (called the test digit).
• If the test digit is 5 or greater, round up by
  adding 1 to the rounding digit .
• If the test digit is less than 5, round down by
  keeping the rounding digit the same .

10
(No Transcript)
11
(No Transcript)
12
Reading Bar Graphs
2.75
2.25
13
Reading Line Graphs
1.25
14
Examples

• Round 63,427 to the nearest hundred.
• Round 76,003 to the nearest ten thousand.
• Round 1,259,561 to the nearest thousand.

15
Adding and Subtracting Decimals
We can use the same rules for adding and
subtracting integers when adding or subtracting
decimals .
16
Adding Decimalswith the same signs.

• To add two numbers with the same signs, add their
  absolute values. The answer will have the same
  sign as the numbers being added.

17
Adding Decimalswith different signs.

• To add two decimals with different signs,
  subtract their absolute values, the smaller from
  the larger. Then attach to that result the sign
  of the number with the larger absolute value.

18
Subtracting Decimals

• To subtract two decimals, change the subtraction
  into an addition by adding the opposite of the
  number being subtracted.

19
Adding or Subtracting Decimals.

• To add or subtract two decimals, use column
  notation and line up the decimal points.
• Add or subtract the numbers as you would whole
  numbers.
• Write the decimal point in the result directly
  below the decimal points in the problem.

20
Examples

• 4.123 5.35
• 3.45 7.1224
• 57.443.124
• 3.452.335.895

21
Examples

• 7.73 - 5.45
• 45.12-13.775
• 23.125-13.5
• 6.23-4.122

22
More complicated examples.

• -6.2334.25
• 5.19-14.25
• -2.44-5.75
• -12.27-7.92

23
Application Examples
Use the following graphs, determine how much
profit the company made or lost for the entire
year.
24
Bar Graphs
2.25
25
Line Graphs
-0.25
26
Multiplying Decimal Numbers

• Multiply the numbers as if they were whole
  numbers by using column notation and ignoring the
  decimal points.
• Place the decimal point in the answer so that the
  result has the same number of decimal places as
  the sum of the decimal places in each factor.
• The product of two positive or two negative
  numbers is a positive number. The product of a
  positive and a negative number is a negative
  number.

27
(No Transcript)
28
(No Transcript)
29
Multiplying by powers of 10

• 10110
• 102100
• 1031,000
• 10410,000
• To multiply a decimal by a power of 10, move the
  decimal point the same number of places to the
  right as the number of zeros in the power of 10.

30
(No Transcript)
31
Order of Operations Agreement

• Parentheses first.
• Exponents next.
• Multiplication or
• Division.
• Addition or
• Subtraction.
• Operations on the same level performed from left
  to right.

32
(No Transcript)
33
(No Transcript)
34
Dividing a Decimal Numberby a Whole Number

• Write the problem in long division form.
• Divide as if working with whole numbers.
• Write the decimal point in the result directly
  above the decimal point in the dividend. If
  necessary, additional zeros can be written to the
  right of the dividend to allow the division to
  proceed.

35
(No Transcript)
36
Dividing a Decimal Numberby a Decimal Number

• Move the decimal point of the divisor so that it
  becomes a whole number.
• Move the decimal point of the dividend the same
  number of places.
• Divide as if working with whole numbers.
• Write the decimal point in the result directly
  above the decimal point in the dividend.

37
(No Transcript)
38
Dividing by powers of 10

• 1/11.0
• 1/100.1
• 1/1021/1000.01
• 1/1031/1,0000.001
• 1/1041/10,0000.0001
• To divide a decimal by a power of 10, move the
  decimal point the same number of places to the
  left as the number of zeros in the power of 10.

39
(No Transcript)
40
Order of Operations Agreement

• Parentheses first.
• Exponents next.
• Multiplication or
• Division.
• Addition or
• Subtraction.
• Operations on the same level performed from left
  to right.

41
(No Transcript)
42
(No Transcript)
43
Fractions and Decimals

• To write a fraction as a decimal, use long
  division to make the conversion.

44
(No Transcript)
45
Rounding Repeating Decimals

• Sometimes when converting a fraction into a
  decimal, the long division never ends. In this
  case you may use bar notation, or round to some
  given place value.

46
(No Transcript)
47
Rounding Decimal Numbers

• Locate the digit in the place you are rounding to
  (called the rounding digit).
• Look at the digit to the right of the rounding
  digit (called the test digit).
• If the test digit is 5 or greater, round up by
  adding 1 to the rounding digit and remove all the
  digits to the right of the rounding digit.
• If the test digit is less than 5, round down by
  keeping the rounding digit the same and remove
  all of the digits to the right of the rounding
  digit.

48
(No Transcript)
49
Order of Operations Agreement

• Parentheses first.
• Exponents next.
• Multiplication or
• Division.
• Addition or
• Subtraction.
• Operations on the same level performed from left
  to right.

50
(No Transcript)
51
(No Transcript)
52
(No Transcript)
53
(No Transcript)
54
(No Transcript)
55
(No Transcript)
56
(No Transcript)
57
(No Transcript)
58
(No Transcript)
59
(No Transcript)
60
Problem Solving

• Analyze the problem.
• Define your variables.
• Form an equation.
• Solve the equation
• Check the solution
• State the conclusion

61
(No Transcript)
62
(No Transcript)
63
(No Transcript)
64
Squares and Square Roots
65
(No Transcript)
66
(No Transcript)
67
(No Transcript)
68
(No Transcript)
69
(No Transcript)
70
(No Transcript)
71
(No Transcript)
72
(No Transcript)
73
(No Transcript)