Tag Archives: Singapore

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

Con­tinue read­ing

  

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 =

Con­tinue read­ing

  

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

Con­tinue read­ing

  

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

Con­tinue read­ing

  

Primary 3 Money Level 2 Ex 1

P3-Money-L2-Ex 1

Ans:

1–  $44

Amount of money she spent ->  $100 — $12 = $88

$88 ÷ 2 = $44

 

2–  3410¢

3–  $173.80

Cost of a fan ->  $99.85 — $25.90 = $73.95

Total cost –>  $99.85 + $73.95 = $173.80

 

4—  7 coins

5–  $5.55

6–  8 pack­ets 

Amount of money Janet spent -> $20 — $4  = $16

$16 ÷ $2 = 8 pack­ets 

Con­tinue read­ing

  

Primary 6 July Problem Sums 6

P6-July-PSP-Ex 6

Ans:

1–  $800

Frac­tion of money spent on food and shoes –>  1/4 + 1/5 = 9/20

20/20 — 9/20 = 11/20

11u –>  $340 + $100 = $440

1u –> $40

20u –>  $40 ×  20 = $800

 

2–  14 cook­ies

Muffins   :   Cookies

At first  ——>           [   5             :         6   ]  × 2

In the end   ——>    [   2             :        1  ]  × 5

[Make the units of muffins at first and in the end the same]

Muffins   :   Cookies

At first  ———>             10          : 12

In the end  ——->           10          : 5

12u –>  24 cookies

1u –>  2 cookies

5u –>  10 cook­ies left

24 — 10 = 14 cook­ies 

 

3–  Joseph spent more by $2000

3/5 of Terry’s money is equal to 1/3 of Joseph’s money.

[Make the numer­a­tor common]

3/5 of Terry’s is equal to  3/9 of Joseph’s.

Terry   :   Joseph
5         : 9

14u –> $7000

1u –> $500

Amount Terry spent –>  $500 × 5 = $2500

Amount Joseph spent –>  $500 × 9 = $4500

$4500 — $2500 = $2000

Con­tinue read­ing

  

Primary 4 July Problem Sums 2

P4-July-PSP-Ex 2

Ans:

1–  $144

1/2 u –> $36

1u –>  $36 × 2 = $72

$72 × 2 = $144

 

2–  $487.80

3–  6  4/5 kg

4–  2637 more seashells
Qn 4

7u –>  6328 — 623 = 5705

1u –> 815

Jan­ice –>  815 × 7 = 4075 seashells

Car­o­line –>  815 + 623 =1438 seashells

4075 — 1438 =  2637 more seashells

Con­tinue read­ing

  

Primary 3 July Review 1

P3-Jul-Review 1

Ans:

1–  3

2–  3

3–  2

4–  4

5–  4

6–  2

Grandmother’s age now —  9 × 9 = 81  Con­tinue read­ing

  

Primary 6 July Problem Sums 5

P6-July-PSP-Ex 5

Ans:

1–  95

[Use trial and error from the largest 2-digit mul­ti­ple of 9]

Great­est pos­si­ble 2-digit mul­ti­ple of 9 –> 99

99 + 5 = 104 (wrong: answer is not 2-digit)

90 + 5 = 95 (correct)

 

2–  100 grey squares and + 99 white tiles

Num­ber of grey tiles –> Pat­tern Num­ber × 2

50 × 2 = 100 grey tiles

Num­ber of white tiles –>  Num­ber of grey tiles — 1

100 — 1 = 99 white tiles

 

3–  108 teach­ers

Pupils  –>                      Boys  :  Girls
4     : 5

5u –> 2400

1u –> 280

9u –>  280 × 9 = 4320 children

Teach­ers  :  Pupils
1          : 40

40u –> 4320

1u –>  108 teach­ers

 

4–  14 years old

Nicholas’ age now –>  35 — 8 = 27 years old

Timothy’s age now –>  1/3 × 27 = 9 years old

9 + 5 = 14 years old

Con­tinue read­ing