Sections 5.1 – 5.3

Sections 5.1 – 5.3

Place Value Chart

Write the name:
1. 3/10 = three tenths
Section 5.1
2. 7/100 = seven hundredths
3. .54 = fifty four hundredths
4. .125 = one hundred twenty five thousandths
- Make sure there is a ths on the end of each of
those names!

Write as a fraction:
Section 5.1
Example: .4 the 4 is in the tenths spot so put the 4
over a 10 so I have 4/10 which simplifies to 2/5
Example: .31 the 1 is in the hundredths spot so put
the 31 over a 100 so I have 31/100
Example: 2.53 the 2 is off to the side, the 3 is in the
hundredths spot so it is 2 53/100

Section 5.1
Rounding: same as in first unit
Example: 3.356 round to nearest tenth
3.356 the 5 says to round up one and
everything after becomes a zero so we get:
3.400
Example: 3.343 round to the nearest hundredth
The 3 says to keep it the same so we get:
3.340

Section 5.2
Add/Subtract Decimals:
Line them up, and do regular operations:
Example: 13.456
- 2.353
11.103 brought the decimal straight down
Example: 4.58 – (-2.42) Rewrite: 4.58 + 2.42
4.58
+ 2.42
7.00

Finding missing values:
x
4
8
y
7
To find y-values:
Look at horizontal pieces. You
have one that is 4 and 7 units
long. So the long piece, y is 11
units
Section 5.2
5
To find x-value:
Look at the up/down
or vertical pieces.
You have one that is
8 units the other is 5
units so all together
is 13 units which is x
or the long piece
To find perimeter:
add all the sides
now:
4+8+7+5+13+11
55 units

Section 5.3
Multiply decimals:
I don’t line them up, I do it this way:
2.35
x .4
9 4 0
So my answer:
.940
I don’t line the decimals up.
I do regular multiplication
and then count how many
times the decimal moved all
together. In the first # it
moved twice.
Second # it moved once.
So I move my decimal in my
answer a total of 3 spaces.

Circles:
Section 5.3
Radius is from center of circle to edge
Diameter is from one edge to the other edge
If given diameter to find radius cut diameter in
half!
Example: Diameter = 6ft then Radius = 3ft
If given radius double it will give you diameter
Example: Radius = 7 ft then Diameter = 14ft

Circumference of a Circle:
2∏r
Section 5.3
remember pie = 3.14, r = radius
Example: Given a circle with a radius of 3 ft
Circumference = 2(3.14)(3) so multiply all
together
= 6(3.14)
= 3.14
x 6
18.84ft
Plug into formula
Multiply in any order, so I
multiplied 2 and 3 first got
6
Then multiplied 6 and 3.14
and got 1884 but moved
decimal 2 spots over.
Always label answer in the
correct units

Section 5.3
Circumference of a Circle:
2∏r = Circumference
Example: Given circle with diameter of 8 ft
So the radius is 4 ft so my formula is:
2(3.14)(4) = circumference
8(3.14) = circumference
3.14
x 8
25.12ft

5.1: page 287: 11 – 41 odd, 45 – 55 odd, 81 – 87 odd:
Identify place value:
11. 3.983 13. 440.39 15. 489.02 17. -9.28345 19. .489
21. -93.834
Write the word name:
23. 9/10 25. 23/100 27. -33/1000 29. 407/10000
31. 3.24 33. -5.9 35. 52.3 37. 6.219
Write as a number:
39. Negative eight thousand, four hundred seventy-two and fourteen
thousandths
41. Seven hundred and seven hundredths
Write as a fraction:
45. 3.7 47. 2.8 49. .25 51. -.55 53. 20.812 55. -15.0005
Round to nearest place value:
81. 49.943 83. 33.416 85. -9.0955 87. 21.0239

5.2: page 295: 33 – 57 e.o.o, 69:
Add/Subtract:
33. 14.5 – 8.823 37. 55.9 – 34.2354 41. 183.01 – 23.452
45. -506.34 + 83.4 49. 47.82 – (-3.159) 53. 5 – 9.432
57. -28.3 + (-82.9)
Find values and perimeter:
27.3 inch
69. 6.7 inch
22.1 inch
x
y
18.4 inch

5.3: page 306: 9 – 15 odd, 35, 37, 59 – 75 odd:
Multiply:
9. .8 x .5 11. .9 x 4 13. -60 x -.003 15. 22.38 x .8
35. 34.9 x 100 37. 96.59 x 1000
Simplify:
59. .4 61. 1.3 2
63. 3
65.
2
67. Skip
69. Find diameter when radius is 6.1 inch
71. Find radius when diameter is 166 m
Find the circumference of the circle:
73. Given: diameter is 20 cm
75. Given: radius is 2.5 km
2
.1 .2