Category Archives: Primary 5

Primary 5 Ratio Level 2 Ex 5

P5-Ratio-L2-Ex5

Ans:

1–  4

2–  $59

12u –> $354

1u –> $29.50

$29.50 × 2 = $59

 

3–  12 : 16 = 3 : 4

4–  3 : 7

5–  2 : 3

Breadth –>  30 – (9 × 2 ) /2 = 6 cm

6 : 9 = 2 : 3

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Primary 5 CA1 Revision 12

P5-CA1-Ex12

Ans:

1–  $384

Christina –>  1u

Molly ->  3 u

Jack –>  1u + $65

5u + $65 = $705

5u –>  $705 – $65 = $640

1u –>  $640/5 = $128

$128 × 3 = $384

 

2–  235 paper clips

Before:                      Tom               :                   Jenny
1                   :                           5

——->     2                  :                         10

After:                             1                   :                           2

——>      5                  :                       10

5u – 2u = 4u

3u –>  141 clips

1u –>  47 clips

47 × 5 = 235 paper clips

 

3–  $60

3u –>  $36

1u –>  $12

$12 × 5 = $60

 

4–  9 years’ time

[Constant Difference]

3u –>  51 years

1u –>  17 years old

17 – 8 = 9 years’ time

 

5–  See belowQn 5

 

 

 

 

 

 

 

 

 

6–  18 coins

Multiples of 5 –>  5         10           15
+ 3  ->  8         13           18

Multiples of 4 –>   4         8             12            16
+ 2 ->   6         10          14           18

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Primary 5 CA1 Revision 11

P5-CA1-Ex11

Ans:

1–  3 000 303

2–  8

3–  49   1/2

4–  2500

5–  4   5/12

6–  18

7–  2   31/48

8–  2   19/24 kg

9–  $104

Cost of 4 pens –>  4 × $12 – $48

$48 + $56 = $104

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Primary 5 CA2 Revision 1

P5-CA2-Ex 1

Ans:

1–  3

2–  1

3–  2

Area of square –>  8 cm × 10 cm = 80 cm²

Base of triangle –>  14 cm – 8 cm = 6 cm

Area of triangle –>  1/2 × 6 cm × 10 cm = 30 cm

80 cm + 30 cm = 110 cm²

 

4–  3

5–  2

1 hour –> 60 min × 60 = 3600 sec

3600/100 = 36 sets of 100 seconds

36 × 10 = 360 lollipops

 

6–  2

11.00 a.m. to 12 p.m. –>  $2

12 p.m. to 2.30 p.m. –>  2.5 hours ≈ 3 hours –> 3 × $1 = $3

$3 + $2 = $5

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Primary 5 July Review 3

P5-Jul-Review 3

Ans:

1–  2

2–  2

3–  2

4–  4

5–  3

0.8 = 8/10 = 4/5

Left–>  5/5 – 4/5 = 1/5

1u –>  $3420

$3420 ×  4 = $13 680

 

6–  4

7–  1

Total amount of sugar –>  21 × 4 kg = 84 kg

84/8 = 10 4/8 = 10  1/2 kg

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Primary 5 June Review 1

P5-June-Review 1

Ans:

1–  3

2–  3

3–  2

4–  3

5–  1

6–  2

7–  2

8–  4

40 : 45 = 8 : 9 = 16 : 18

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Primary 5 SA1 Revision 5

P5-SA1-Ex 5

Ans:

1–  200 0002 hundred thousands

2–  15 600

3–  298

4–  9

5–  9 : 7

$81 – $18 = $63 (Marianne’s)

Alison   :   Marianne
81       :      63
–>    9     :      7

 

6–  3

15 × 3/10 = 4   1/2

4   1/2 ÷  3/2 = 3

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Primary 5 Ratio Level 1 Ex 5

P5-Ratio-L1-Ex 5

Ans:

1–  2

2–  4

3–  3

Local   :   Foreign
3        :     5

3u + 5u = 8u

8u –>  120 stamps

1u –>  120/8 = 15 stamps

15 × 3 = 45 local stamps

 

4–  3

5–  3

Perimeter –>  Length + Breadth + Length + Breadth
->     3u        +    1u         +    3u       +      1u  = 8u

8u –> 40 cm

1u –>  40/ 8 = 5 cm

5 cm × 3 = 15 cm

 

6–  3

Son’s age –>  42 – 28 = 14 years old

42  :  14 =  3  :  1

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Primary 5 March Review 3

P5-Mar-Review 3

Ans:

1–  3

2–  3

4  1/4 = 17/4

17/4 = 34/8

 

3–  4

4–  2

Length of String Q –>  3  1/5 m –  1  2/3 m = 1  8/15 m

1  8/15 m + 3  1/5 m = 4  11/15 m

 

5–  2

Remaining pizza after Joseph had eaten it –>  8/8 – 1/8 = 7/8

4/5 × 7/8 = 7/10

 

6–  1

Breadth of rectangle–>  (48 cm÷ 2) – 14 cm = 10 cm

14 cm × 10 cm = 140 cm²

 

7–  2

8–  2

(24 sweets  cost the same as 18 chocolates )  ÷ 3

8 sweets cost the same as 6 chocolates

18 – 6 = 12 chocolates 

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Primary 5 October Problem Sums 5

P5-PSP-Oct-Ex5

Ans:

1–  $6588

2–  2400 cm³

Amount of water at first –>  4/5 × 30 cm × 20 cm × 30 cm = 14 400 cm³

Amount of water in the end –>  2/3 × 30 cm × 20 cm × 30 cm = 12 000 cm³

14 400 cm³ – 12 000 cm³ = 2400 cm³

 

3–  38 marbles

Qn 3

2u –>  96 – 60 = 36

Barry –>  36 ÷ 2 = 18 marbles

Joe –>  60 – 18 = 42 marbles

Tom –>  18 × 3 = 54 marbles

Total –> 54 + 42 + 18= 114 marbles

114 ÷ 3 = 38 marbles

 

4–  Cup Y —  160 ml    ,   Cup Z —  60 ml

Y   :   Z
8   :    3

8u + 3 = 11u

11u ÷ 2 = 5.5u

8u – 5.5u = 2.5u

2.5u –>  50 ml

1u –>  20 ml

Cup Y –>  20 ml × 8u = 160 ml

Cup Z –>  20 ml × 3 = 60 ml

 

5–  $651.80

Qn 5

2u –>  $1505 – $201.40 = $1303.60

$1303.60 ÷ 2 = $651.80

 

6–  $15.50

Qn 6

 

2u–  $108 – $71 = $37

1u —  $18.50

Megan –> $18.50 × 3 = $55.50

$71 – $55.50 = $15.50

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