Tag Archives: Singapore

Primary 6 Algebra Level 2 Ex 5

P6-Algebra-L2-Ex5

Ans:

1–  $(7y/2) /  $3.50y

Price of 1 durian –>  $(y/10)

$(y/10) × 35 = $(7y/2)/ $3.50y

 

2–  55

3–  (35 

4–  (4+ 10) years old

Brother’s age –>  3n + 9 — 2n = (n + 9) years old

Total age now –>  3n + 9 + n + 9 = 4n + 18 years old

4n + 18 – 4 – 4 = (4n + 10) years old

 

5–  $(m – 20)/3

6–  4.5z² cm²

Area of Tri­an­gle WXY –>  1/2 × 3z × 1.5= 2.25 z² cm²

2.25 z² × 2 = 4.5z² cm²

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Primary 3 Whole Numbers Level 3 Ex 4

P3-Whole Numbers-L3-Ex 4

Ans:

1–  4200 beads

Qn 1

Num­ber of beads Jen­nifer has –>  1866 + 468 = 2334

2334 + 1866 = 4200 beads

 

2–  195 steps

3–  67 cook­ies

4–  a –>  1277 men   ,   b ->  1085 more men

Num­ber of men who par­tic­i­pated –>  1277 — 89 = 1188

Num­ber of women who par­tic­i­pated –>  123 — 20 = 103

1188 — 103 =1085 more men 

 

5–  5460 stick­ers 

Num­ber of months from Feb­ru­ary to Octo­ber –> 9

9 × 20 = 180 more than January

5280 + 180 = 5460 stick­ers

 

6–  $712

Total amount of money Melody and Lisa have –>  $2835 + $4259 = $7094

Amount of money each of them has in the end –>  $7094 ÷ 2 = $3547

$4259 — $3547 = $712

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Primary 2 Whole Numbers Level 1 Ex 1

P2-Whole Numbers-L1-Ex 1

Ans:

1–  1

2–  3

3–  2

1 rec­tan­gle –>  16 ÷ 2 = 8

8 + 3 = 11

 

4–  3

9 + 3 + 9 + 3 = 24

24 ÷ 4 = 6

 

5–  2

6–  4

7–   Con­tinue read­ing

  

Primary 6 Algebra Level 1 Ex 4

P6-Algebra-L1-Ex 4

Ans:

1–  1

2–  1

3–  4

12x + 19 + (4x × 6 ÷ 3) – 8
= 12x + 19 + 8x - 8 = 20x + 11

 

4–  2

5–  2

Amount left after giv­ing her daugh­ter —  $(800 — 40z)

Each son ->  $(800 — 40z) ÷ 3

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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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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

  

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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