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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Maths Classes for 2015

Small group/1-to-1 tuition classes for 2015

Lessons will start mid-November.

Group classes will be con­ducted with no more than 6 students.

I will pro­vide all work­sheets and test papers at no extra cost.

Unfor­tu­nately, for indi­vid­ual lessons, I can only accept stu­dents liv­ing in the East.

Group classes — 2 hours per les­son, $120 for 4 lessons.
Loca­tion — Still Road (near­est MRT — Eunos)

1-to-1 lessons — 1.5 hour per les­son, $50 per hour.

Feel free to call/sms/email me at 91603500; ange@talkingmaths.com  for more infor­ma­tion, no obligations!

 

 

 

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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 5 Volume Level 3 Ex 2

P5-Volume-L3-Ex 2

Ans:

1–  32 768 cm³ 32.768 l

3/4 — 5/8 = 1/8 poured out

1/8 × 64 cm × 64 cm × 64 cm = 32 768 cm³ / 32.768 l

 

2–  16 800 cm³16.8 l

3–  300 ml

4/5 — 1/2 = 3/10 filled

3/10 × 10 cm × 10 cm × 10 cm = 300 cm³ = 300 ml

 

4–  720 ml

8 cm — 5 cm = 3 cm

Amount of water poured out –>  40 cm × 30 cm × 3 cm = 3600 cm³

3600 cm³ ÷ 5 = 720 cm³ = 720 ml

 

5–  25 cm

Length   :   Breadth
4        : 1

4u — 1u = 3u

3u –>  6 cm

1u –>  2 cm –>  breadth

Length –>  2 cm × 4 = 8 cm

Base area –>  2 cm × 8 cm = 16 cm²

400 ÷ 16 = 25 cm

 

6–  17.5 cm

1600 cm³ ÷ 640 cm² = 2.5 cm

2.5 cm + 15 cm = 17.5 cm

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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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Maths Group Tuition Classes

Maths Group Tuition (4 — 6 stu­dents) at Still Road.

Avail­able slots:

Wed: 4 — 6 p.m.

Sat:  10 a.m. — 12 p.m. NEW!

Sat: 1 — 3 p.m.

I have more than 17 years of expe­ri­ence.
Inten­sive drilling on prob­lem sums

Free work­sheets and test papers.

Improve­ment guaranteed!

Afford­able and effective!

4 lessons (2 hours each) for $120

1 free trial class

 

For more infor­ma­tion, call/sms me at 9160 3500, email me at ange@talkingmaths.com

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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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Time Management

With the PSLE just around the cor­ner, this is a great time to remind all the kids tak­ing the Maths paper to work on their time man­age­ment. I always feel it would help if I had an extra 10 minutes.

 

Paper 1 -> 30 ques­tions, 50 minutes

50 ÷ 30 ≈ 1.6 min per question.

 

Paper 2 -> 18 ques­tions (5 Short-answer ques­tions + 13 Long-answer ques­tions), 1 hour 40 min

SAQ -> 15 min

15 ÷ 5 = 3 min per question

LAQ-> 1 hour 25 min

85 ÷ 13 ≈ 7.5 min per question

Well, even with this esti­ma­tion, the kids have to be really metic­u­lous with their work as I have not left any time for check­ing. Ide­ally, of course, it would be good to leave 15% of the time allo­cated to do some checking.

Well, good luck to the kids tak­ing the PSLE! The next few weeks, make sure they are famil­iar with all the com­mon prob­lem sums. They should be well-prepared for Paper 1 too. Noth­ing less than 34/40 !

Image

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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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