Tag Archives: revision

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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Primary 4 October Problem Sums 4

P4-Oct-PSP-Ex 4

Ans:

1–  208 chicken pies

2–  17  1/3 kg

3–  $144

Qn

 

1u –>  $36 + $36 = $72

$72 × 2 = $144

 

4–  7 cm

Area of big rec­tan­gle –>  14 cm × 9 cm = 126 cm²

Area of unshaded rec­tan­gle –>  126 cm² — 98 cm² = 28 cm²

Length of AB –>  28 cm² ÷ 4 cm = 7 cm

 

5–  35 min­utes

Time the piano les­son ended —>  1h 40 min after 11 30 –>  13 10

Time dura­tion between 13 10 and 13 45 —>  35 min­utes

 

6–  32.5 kg

Ali­son + Brenda –>  61.5 kg
Ali­son + Chris­tine –>  67 kg
Brenda + Chris­tine –> 63.5

61.5 kg + 67 kg + 63.5 kg = 192 kg

A + A + B + B + C + C –>  192 kg

A + B + C –>  192 kg ÷ 2 = 96 kg

96 kg — 63.5 kg = 32.5 kg

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Primary 3 October Review 1

P3-Oct-Review 1

Ans:

1–  2

2–  1

3–  4

4–  4

5–  1

6–  2

7–  2

Total length of Parts A and B –>  21 m — 9 m = 12 m

Qn 7

3u –>  12 m

1u –>  4 m

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Primary 3 September Review 1

P3-Sep-Review 1

Ans:

1–  1

2–  4

75 × 5 = 375

375 + 90 = 465

 

3–  4

4–  1

5–  4

14 hun­dreds and 47 tens = 1400 + 470 = 1870

1870 + 847 = 2717

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Primary 6 September Problem Sums 10

P6-PSP-Sep-Ex 10

Ans:

1–  See below

Qn 1

 

2–  9360 cm³

Height of water needed to fill the con­tainer –>  25 cm — 18.5 cm = 6.5 cm

45 cm × 32 cm × 6.5 cm = 9360 cm³

 

3–  68 but­tons

36 + 3 = 39 more buttons

8 — 5 = 3  buttons

∴ She needs 39 more but­tons because she is putting 3 more but­tons into each box.

39 ÷ 3 = 13 boxes

13 × 5 + 3 = 68 but­tons

 

4–  $580

107% –>  $465.45

100% –>  $435 (dis­counted price with­out GST)

75% –> $435

100% –>  435/75 × 100 = $580

 

5–  136 chil­dren

40% = 40/100 = 2/5

2/3 of the boys = 2/5 of the girls

Boys  :  Girls
3      : 5

2u –> 34

1u –> 17

17 × 8 = 136 chil­dren 

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Primary 5 September Review 1

P5-Sep-Review 1

Ans:

1–  3

2–  2

3–  3

4–  4

7u –> $756

1u –> $108

10u–>  $108 × 10 = $1080

 

5–  1

6–  3

80% –> $1800

1% –>  $22.50

100% –>  $22.50 × 100 =  $2250

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Primary 4 August Review 4

P4-Aug-Review 4

Ans:

1–  3

2–  3

3–  2

4–  4

5–  4

7.25 a.m. to 9.25 a.m (2 hour) –>  8 quarter-turns

8.25 a.m. to 9.40 a.m. (15 min) –>  1 quar­ter turn

8 + 1 =

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Primary 6 August Review 6

P6-Aug-Review6

Ans:

1–  4

2–  1

Total of the 4 num­bers –>  4 × 22 = 88

88 — 24 — 26 — 28 = 10

 

3–  1

4–  4

15/60 × 300 km = 75 km

75 km = 75 000 m

 

5–  4

6–  4

5/5 — 2/5 = 4/5  (owned cats and dogs)

3/5 –>  48 + 72 = 120 children

1/5 –>  40 children

5/5 –>  40 × 5 = 200 chil­dren

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Primary 5 Average Level 3 Ex 4

P5-Average-L3-Ex4

Ans:

1–  432 more stamps

Total num­ber of stamps Jamie and Patrick had ->  360 × 2 = 720

Patrick -> 1u

Jamie -> 4u

5u –>  720 stamps

1u –>  144 stamps

4u — 1u = 3u

3 × 144 = 432 more stamps

 

2–  71.5 kg

Total mass of 3 boys if they weigh as much as Derek –>  75 × 3 + 12 + 9 = 246 kg

Derek’s mass  –>  246 kg ÷ 3 = 82 kg

Joe’s actual mass ->    82 kg — 12 kg = 70 kg

Ron’s actual mass ->  82 kg — 9 kg = 73 kg

Aver­age mass of Joe and Ron –>  (70 + 73) ÷ 2 =  71.5 kg

3–  5.8 m

Total mass of the pole, plank and rod –>  4.8 m × 3 = 14.4 m

Rod –> 1u

Pole –> 2u

Plank –>  2u + 0.4 m

5u +  0.4 m ->  14.4 m

5u –>  14.4 m — 0.4 m = 14 m

Rod  –>  14 m ÷ 5 = 2.8 m

Pole –>  2.8 m × 2 = 5.6 m

Plank –>  2.8 m × 2 + 0.4 = 6 m

Aver­age length of pole and plank –>  (5.6 m + 6 m ) ÷ 2 = 5.8 m

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Primary 4 July Problem Sums 3

P4-July-PSP-Ex 3

Ans:

1–  $9153

$2178 + $6975 = $9153

 

2–  5  5/12 kg

The total mass of the nails–>  9   11/12 kg —   11/12 kg = 9 kg

Mass of the nails when they are half-filled –>  9 /2 = 4   1/2 kg

4   1/2 kg +  11/12 kg = 5   5/12 kg

 

3–  3456 canned drinks

128 × 27 = 3456 canned drinks

 

4–  56.58 kg

Qn 4

6u –>  169.74 kg

1u –>  28.29 kg

28.29 kg × 2 = 56.58 kg

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