20
Mental Maths. Sheet 2.
Monday
Tuesday
Wednesday Thursday
Friday
4x7
8x6
7 x 10
58 + 7 - 20
7 000 + 30 + 600
8x7
5x4
7 x 100
34 + 44 - 30
3 + 70 + 3 000
6x7
9x8
7 x 1 000
53 + 33 - 20
600 + 4 + 5 000
1x7
7 x 10
7 x 10 000
68 + 29 - 30 8 000 + 20 + 400
3x7
4x8
70 x 10
63 + 13 - 20 70 + 9 000 + 100
5x7
5 x 10
70 x 100
79 + 90 - 30
7 + 200 + 3 000
0x7
9x4
70 x 1 000
87 - 45 + 20
70 + 0 + 6 000
10 x 7
6x9
3 x 10
62 - 36 + 30 2 200 + 170 + 300
7x7
8 x7
3 x 100
55 - 29 + 20 1 600 + 700 + 90
9x7
7x6
3 x 1 000
45 - 17 + 30 1 000 + 340 + 50
2x7
4x7
3 x 10 000
74 - 30 + 20 4 123 + 3 000 + 70
63 ÷ 7
10 x 6
30 x 10
32 - 16 + 30 600 + 169 + 5 000
35 ÷ 7
6x6
30 x 100
24 + 34 - 20
8 + 3 000 + 700
14 ÷7
4x6
30 x 1 000
63 + 19 - 30 440 + 300 + 300
42 ÷ 7
10 x 10
8 x 10
62 + 26 - 20 2 400 + 160 + 20
28 ÷ 7
180 ÷ 10
8 x 100
87 + 19 - 30 120 + 5 000 + 400
70 ÷ 7
100 ÷ 10
8 x 1 000
64 + 17 - 20 350 + 350 + 4 200
56 ÷ 7
220 ÷ 10
8 x 10 000
26 + 71 - 30
8 000 + 4 000
49 ÷ 7
2 200 ÷ 100
80 x 10
43 - 17 + 20
8 000 - 4 000
21 ÷ 7
6 300 ÷ 10
80 x 100
59 - 37 + 30
7 000 - 3 000
7 + 7 + 7 + 7 + 7 6 300 ÷ 100
80 x 1 000
65 - 58 + 20
7 000 + 5 000
42 + 7
6 000 ÷ 100
82 x 100
84 - 62 + 30
3 000 + 5 000
28 - 7
6 000 ÷ 10
6 x 10
48 - 29 + 20
8 000 - 3 000
63 - 7
6 000 ÷ 1 000
6 x 100
64 - 48 + 30
9 000 + 2 000
35 + 7
780 ÷ 10
6 x 1 000
78 + 80 - 20
6 000 - 3 000
56 + 7 + 7
7 800 ÷ 10
6 x 10 000
94 + 50 - 30
7 000 + 6 000
21 + 7+ 7
7 800 ÷ 100
60 x 10
65 + 70 - 20
5 000 - 2 000
35 - 7
370 ÷ 10
60 x 100
75 + 31 - 30
3 000 + 5 000
63 + 7 + 7
3 020 ÷ 10
60 x 20
83 + 73 - 20
3 000 - 1 000
56 - 7
4 500 ÷ 100
60x 200
44 + 80 - 30
7 000 + 4 000
21
Unit 3.
Common Fractions.
What are fractions?
When we divide an object (like a cake) or a group of objects (like marbles)
into equal parts, each part is a fraction of the object or group of objects.
There are 8 marbles so 1 marble is ⅛ (one eighth)
The cake is divided into 8 equal pieces so each piece is an eighth.
Activity 1.
Meaning of fractions.
You have learned about these fractions in grade 5.
22
1.Write the correct fraction with the correct meaning.
Example
thirds
3 = parts.
a. thirds
4 = parts
b. eighths
2 = parts
c. halves
5 = parts
d. tenths
3 = parts
e. quarters
8 = parts
f. fifths
10 = parts
g. sixths
12 = parts
h. ninths
7 = parts
i. twelfths
10 = parts
j. sevenths
6 = parts
k. elevenths
9 = parts
l. tenths
11 = parts
2. Which squares have not been divided into quarters (4 = parts)?
3. Which shapes have not been divided into thirds (3 = parts)?
23
4. Write the fraction shaded, the fraction unshaded and the number of equal parts for
each.
Fraction shaded Fraction unshaded No. of = parts.
a.
b.
c.
d.
e.
f.
g.
1
4
3
4
4
24
Let’s look at fractions of groups of
objects.
There are 12 marbles altogether.
A quarter of the marbles are green.
5. Write the fraction shaded, the fraction unshaded and the number of objects in each
group.
Objects.
No. of objects
in the group.
a.
b.
c.
d.
Fraction shaded. Fraction unshaded.
25
Activity 2.
Equivalent fractions.
1. Use the fraction wall to work out an equivalent fraction.
1
2
a. 2= 8
1
b. 4=16
1
3
e. 2 = 16
f. 4= 8
2. Write a fraction for each of the letters.
0
a.
b.
1
c. 8=16
d. 2=
g. 1 whole= 8
h. 1 whole=16
c.
1
1
d.
14
Activity 3.
Equivalent fractions and simplifying fractions.
1. Copy and complete.
1
1
1
1
a. 8=16
b. 4= 8
c. 4 = 16
e. 2= 8
f. 2= 4
g. 4= 8
h. 4 = 16
i. 1 whole= 8
j. 1 whole= 4
k. 1 whole=16
l. 1 whole= 2
1
1
3
d. 2=16
3
e.
2
26
2. Write the fractions in their simplest form.
4
Example
=
8
2
4
Still not
simplest form.
Not simplest
form.
1
=
2
Simplest
form.
A fraction in simplest form means I am using the smallest
numbers I can to write the fraction.
6
8
a. 8
4
b. 16
4
10
e. 8
12
c. 16
d. 16
14
f. 16
2
g. 16
h. 8
3. Copy and complete.
1
a. 3= 6
2
d. 3= 6
g. 1 whole= 3
1
b. 6=12
2
e. 3=12
1
c. 3=12
f. 1 whole=12
27
4. Write the fractions in simplest form.
2
4
a. 6= 3
6
b. 6= 3
2
c. 12= 2
4
e. 12= 6
f. 12= 3
10
g. 12= 6
8
d. 12= 3
6
h. 6=
5. If one pizza costs R40:
3
a. what would 8 of a pizza cost?
5
b. what would 8 of a pizza cost?
Comparing and ordering fractions.
1. Use the fraction wall and compare the following fractions. Replace * with ˂ ˃or =.
1
1
1
1
a. 6
e. 7
1
i. 3
8
6
2
6
2
b. 4
2
f. 6
5
j. 10
1
2
1
7
1
2
8
1
7
2
c. 8
g. 8
3
1
1
5
4
d. 3
h. 7
6
5
28
2. Write the fractions from biggest to smallest.
1
a. 3
1
d. 5
1
g. 6
1
10
1
1
2
1
3
10
3
4
1
1
b. 10
1
e. 6
1
2
h. 6
2
3
2
4
2
10
1
2
c. 4 1
5
1
3
1
f. 2
1
1
i. 5
2
5
1
1
3
1
6
10
4
3. Count on and simplify the fractions where possible.
a.
b.
c.
d.
e.
1
2
1
10
7
8
0
0
3
4
6
1
3
=
8 4
1
8
2
3
10
5
1
=
10 2
3
8
5
8
0
1
1
14
1
6
10
12
Activity 2.
Fractions of groups of objects.
The fraction of a group which has been shaded can also be simplified.
9
Examples
12 4
4 2
=
6 3
1. Say what part of each drawing is shaded and then simplify the fraction.
a.
3
=
b.
c.
29
2. Copy and complete. Use the drawings to help you.
Example
1
a. 3 of 6=
2
e. 3 of 6 =
1
4
of 12 = 3
1
b. 8 of 16 =
3
f. 8 of 16 =
1
c. 3 of 12 =
2
g. 3 of 12 =
1
d. 4 of 16 =
5
h. 8 of 16 =
3. Write what fraction of the 2D shapes are:
a. circles?
b. squares?
c. triangles?
d. rectangles?
e. hexagons?
Write each fraction in its simplest
form.
30
4. Copy and complete. If it helps you, use the shapes in the block above.
1
a. 8 of 16 =
3
e. 4 of 16 =
1
b. 16 of 16 =
5
f. 8 of 16 =
3
c. 8 of 16 =
7
g. 8 of 16 =
1
d. 4 of 16 =
15
h. 16
5. Copy and complete.
1
a. 5 of R20=
1
e. 2 of 100 cm
1
b. 4 of R100=
2
f. 3 of 90 cm=
1
1
c. 3 of R60=
3
g. 4 of 90 cm=
6. I walk 3 km to school. I walk 3 of the way with a friend.
How many km do I walk alone?
3
7. I get R40 a month. I save 8 of my money.
How much money did I save?
1
d. 16 of R32=
7
h. 10 of 200 cm=
31
Activity 3.
Tenths and hundredths.
I divide a strip into 10 equal squares.
I colour 3 of the 10 squares.
3
10
1. Write a fraction for each of the following. Simplify where you can.
a.
b.
c.
d.
e.
f.
2. Count on and simplify where you can.
0
1
10
a
b
c
d
e
f
g
9
10
1
32
Hundredths.
Divide a block into 100 squares and shade 28 blocks in.
28
100
3. Write fractions for each of the following. Simplify where you can.
a.
b.
33
c.
4. Copy and complete. Write all your answers in metres.
Example
1
a. 4 km = ----m
2
d. 5 km = ----m
1
g. 10 km = ----m
1
2
1
km = 2 of 1 000 m = 500m
3
b. 4 km = ----m
3
e. 5 km = ----m
3
h. 10 km = ----m
1
c. 5 km = ----m
4
f. 5 km = ----m
7
i. 10 km = ----m
5. Write all of these answers in cents
1
a. 4 of R1= ----c
3
d. 10 of R1= ----c
3
g. 5 of R1= ----c
1
b. 5 of R1= ----c
3
e. 4 of R1= ----c
4
h.5 of R1= ----c
1
c. 10 of R1= ----c
2
f. 5 of R1= ----c
9
i. 10 of R1= ----c
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Activity 4.
Addition and subtraction of fractions with like denominators.
3
2
5
Use a number line: 8 + 8 = 8
1
0
8
3
5
3
2
1
Or, use a diagram: 6 - 6 = 6
5
8
7
8
(= 3)
8
Remember to simplify wherever you can.
1. Copy and calculate. Show your working out.
1
4
a. 6 + 6 =
5
2
d. 8 - 8 =
7
3
g. 12 - 12 =
6
5
j. 7 - 7 =
7
3
4
b. 10 - 10 =
4
3
e. 5
-5=
5
3
7
3
h. 9 + 9 =
k. 11 - 11 =
3
c. 5 + 5 =
3
1
2
2
f. 4 + 4 =
i. 3 + 3 =
7
l. 12 +
5
12
=
35
Addition and subtraction of mixed numbers.
7
112
11
+
112
18
=212
12
=2 + 12 +
6
=312
6
12
1
=32
3
18
-
7
8
3
7
=(8 + 8) - 8
8
11
7
=8 - 8
4
=8
1
=2
2. Copy and complete. Show your working out and ALWAYS simplify where possible.
1
3
2
a. 15 + 15
3
3
e. 24 + 14
7
2
b. 23 + 13
9
i. 110 + 110
1
2
1
3
f. 13 + 13
j. 25 + 15
5
1
c. 26 - 16
5
3
g. 17 - 7
5
5
1
3
5
d. 212 - 12
h. 28 - 18
1
k. 46 - 16
4
5
l. 29 - 9