Tag Archives: PSLE

Primary 6 Prelims Revision 3

P6-Prelims-Ex 3

Ans:

1–  3 : 12 : 17

2–  4.95 cm

Length of the tank –>  180 cm³ ÷ 12 edges = 15 cm

33/100 × 15% = 4.95 cm

 

3–  100 balls

Total units of balls –>  5u + 4u = 9u

Units of balls in each bag in the end –>  9u/2 = 4.5u

5u — 4.5u = 0.5u —>  10 balls

1u –>  10 × 2 = 20 balls

20 × 5u = 100 balls

 

4–  540 km

5–  $24

1 blouse –> 1u

1 pair of jeans –>  1u + $12

3 pairs of jeans + 4 blouses –>  (1u + $12) × 3 + 4u = 7u + $36

7u + $36 -> $204

7u –>  $204 — $36 = $168

1u –>  $24

 

6–  891 beads

Red : Blue + Green
4   : 5

Blue : Green
3    :    8     –> 11u

Adjust the units for the blue and green beads such that they are the same in both cases.

Com­mon mul­ti­ple of 5 and 11 is 55u

There­fore,

Red  :  Blue + Green
44   : 55

Blue  :  Green
15   : 40

Red  :  Blue  :  Green
44 :    15   : 40

44u — 40u = 4u –>  36 beads

1u –>  9 beads

44u + 55u = 99u —->  9 beads × 99 = 891 beads

Con­tinue read­ing

  

Primary 6 SA1 Revision 12

P6-SA1-Ex 12

Ans:

1–  175

2–  $43.50

70% of the price –>  $101.50

30% –>  $101.50/70 × 30 = $43.50

 

3–  (3+ 6) kg

Alan’s mass ->  (+ 3) kg

Nicholas’ mass ->  (m + 3) — 2 = (+ 1) kg

Brett’s mass ->  (+ 1) + 1 = (+ 2) kg

(m + 3) + (+ 1) + (+ 2) = (3+ 6) kg

 

4–  195 km

1  1/2 h× 80 km/h = 120 km

45/60 h × 100 km/h = 75 kg

120 km + 75 km = 195 km

 

5–  $6441.60

Earn­ings in Jan­u­ary –>  122/100 × $6000 = $7320

Earn­ings in Feb­ru­ary –>  88/100 × $7320 = $6441.60

 

6–  30 peo­ple

Frac­tion of men  –>  30/100 = 3/10 = 9/30

Frac­tion of men if 10 women alighted –>  45/100 = 9/20

Women –>  30u — 9u = 21u

20u — 9u = 11u

10u –>  10 women

30 u –>  30 people

Con­tinue read­ing

  

Primary 6 SA1 Revision 11

P6-SA1-Ex 11

Ans:

1–  22

2– $100.00

3–  15 000.02 m

4–  7/8 ,  5/6 ,   1/2 , 1/4

5–  5 p.m.

2 h 15 min before 11.45 a.m. –>  9.30 a.m.

7 h 30 min after 9.30 a.m. –>  5 p.m.

Con­tinue read­ing

  

Primary 6 March Review 7

P6-Mar-Review 7

Ans:

1–  3

2–  4

3–  4

3.30 p.m. to 4.30 p.m. –>  1st hour –> $3.50

4.30 p.m. to 5.45 p.m.–>  1 h 15 min ->  3 sets of half-hours
->  3 × $1 = $3

$3.50 + $3 = $6.50

 

4–  1

5–  2

6–  3

7–  2

75% — 50% = 25%

25% –>  105 ml

50% –>  105 ml × 2 = 210 ml

Con­tinue read­ing

  

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 

Con­tinue read­ing

  

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 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 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 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

  

Primary 6 Circles Level 3 Ex 1

P6-Circles-L3-Ex 1

Ans:

1–  1152 m

Perime­ter of each semi­cir­cle–>  1/2 × 22/7 × 28 = 44 m

2 semi­cir­cles –>  44 × 2 = 88 m

Total perime­ter of track –>  100 + 100 + 88 = 288 m

4 rounds –>  288 m × 4 = 1152 m

 

2–  Area ->  87.5 cm² , Perime­ter –>  39 cm
Area of square –>  7 cm × 7 cm = 49 cm²

Area of quad­rant –>  1/4 ×22/7 × 7 × 7 = 38.5 cm²

Area of fig­ure –>  49 cm² + 38.5 cm² = 87.5 cm²

Perime­ter of quad­rant –>  1/4 × 22/7 × 14 cm = 11 cm

Perime­ter of fig­ure –>  11 cm + 4 × 7 cm = 39 cm

 

3–  34 cir­cles
Qn 3

 

 

 

 

 

Length ->  69 cm ÷ 4 ≈ 17

Breadth -> 9 cm÷ 4 ≈ 2

17 × 2 = 34 cir­cles 

Con­tinue read­ing