Tag Archives: problem sums

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 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 5 July Problem Sums 1

P5-July-PSP-Ex 1

Ans:

1–  $2425
Qn 1

1u –>  $1600 + $750 = $2350

$2350 + $750 = $2425

 

2–  29/45

Amount Diane saves -> $1800 — $640 = $1160

1160/1800 = 29/45

 

3–  4  1/2 kg

Mass of apples when the bas­ket is com­pleted filled –>  8 kg — 1 kg = 7 kg

Mass of apples when bas­ket is 1/2 filled –>  7 kg ÷ 2 = 3  1/2 kg

3  1/2 + 1  = 4  1/2 kg

Con­tinue read­ing

  

Primary 4 July Problem Sums 1

P4-July-PSP-Ex 1

Ans:

1–  63 sweets

2–  $90

Qn 2

2u –>  $75 — $45 = $30
1u –> $15

$15 + $75 = $90

 

3–  96 cook­ies
Qn 3

5u –>  80 cookies

1u –>  16 cookies

6u –>  16 cook­ies × 6 = 96 cook­ies

 

4–  $68
Qn 4

3u –>  $48 + $12 = $60

1u –> $20

$48 + $28 = $68

Con­tinue read­ing

  

Primary 4 June Problem Sums 1

P4-Jun-PSP-Ex1

Ans:

1–  1120 stick­ers
Qn1

9u –>  1260 stickers

1u –>  140 stickers

8u –>  140 × 8 = 1120 stick­ers

 

2–  $28 125

Total num­ber of TV sets sold –>  15 × 5 = 75

$375 × 75 = $28 125 

 

3–  a ->  4 ostriches  ,   b ->  76 more legs

Qn3

 

84 — 8 = 76 more legs   (b)

Con­tinue read­ing

  

Primary 6 June Problem Sums 6

P6-PSP-Jun-Ex 6

Ans:

1–  60 stamps
Qn 1

4u –>  26 + 14 = 40

1u –>  40 ÷ 4 = 10 stamps

6u –> 10 × 6 = 60 stamps

 

2–  6.05 m

Total length of rope Edmond and Mandy had ->  24.6 m + 32.5 m = 57.1 m

57.1 m — 4.2 m = 52.9 m

Length of rope Mandy had in the end –>  52.9 m ÷ 2 = 26.45 m

32.5 m — 26.45 m = 6.05 m

 

3–  13 big water­mel­ons and 5 small watermelons

Assume all 18 water­mel­ons were small –>  18 × $3 = $54

$67 — $54 = $13 (excess)

Since each big water­melon cost $1 more–>  $13 ÷ $1 = 13 big watermelons

18 — 13 = 5 small watermelons

 

4–  See below
Qn 4

Con­tinue read­ing

  

Primary 5 May Problem Sums 2

P5-May-PSP-Ex 2

Ans:

1–  48 mar­bles

[Inter­nal difference/ Con­stant Total]

1u + 7u = 8u (total)

8u ÷ 2 = 4u

4u — 1u = 3u (units Casper received from Zachary)

3u –> 18

1u –> 6

8u –>  6 × 8 = 48 mar­bles

 

2–  $280

Num­ber of months Nikki took to save $7000 –>  $7000 ÷ $140 = 50 months

Num­ber of Months Stephanie took to save $7000 –>  50 — 25 = 25 months

$7000 ÷ 25 = $280

 

3–  732 fewer points

Qn 3

5u –>  1277 — (158 × 4)  = 645

1u –>  645 ÷ 5 = 129

(158 × 3) + (129 × 2) = 732 fewer points

 

4–  $90

Amount of money they had in the end–>  $150 — $20 — $50 = $80

$80 ÷ 2 = $40

$40 + $50 = $90

Con­tinue read­ing

  

Primary 3 SA1 Revision 6

P3-SA1-Ex 6

Ans:

1–  1997 chil­dren

1678 + 1288 = 2966 children

2966 — 969 = 1997 chil­dren

 

2–  234 boxes with 3 cook­ies leftover

2300 — 425 = 1875 cookies

1875 ÷ 8 = 234 boxes R 3 cookies

 

3–  24 sweets left

3 × 12 = 36 sweets (to the boys)

5 × 28 = 140 sweets (to the girls)

140 + 36 = 176 sweets (gave away) 200 — 176 = 24 sweets left

 

4–  768 spec­ta­tors

Num­ber of spec­ta­tors on Sat­ur­day –>  1236 — 240 = 996

3000 — 1236 — 996 = 768 spec­ta­tors

 

5–  24 bot­tles of juice

2 × 4 = 8 bot­tles of orange juice

4 × 4 = 16 bot­tles of grape juice

8 + 16 = 24 bot­tles of juice

  

Primary 5 SA1 Revision 3

P5-SA1-Ex 3

Ans:

1–  4 : 3

Dar­ryl     :     Peter
2          : 5

2/5 × 5u = 2u  (what Peter gave to Darryl)

In the end:    Dar­ryl –>  2u + 2u = 4u

Peter –>  5u –2u = 3u

Dar­ryl     :     Peter
 4         : 3

 

2–  20 kg

Amount of money Laura had –>  $4 × 23 = $92

$92 ÷ $4.60 = 20 kg

 

3–  7200 stamps

36 000 ÷ 5 = 7200 stamps

Con­tinue read­ing

  

Primary 4 SA1 Revision 3

P4-SA1-Ex 3

Ans:

1–  $656

Total cost of both items ->  $5845 + $3499 = $9344

$10 000 — $9344 = $656

 

2–  $1632
Qn 2

$272 ÷ 4 = $68 ( Ryan)

$68 × 3 = $204 (Stephen)Visit Site

$204 × 8 = $1632

 

3–  36 boys

3/4 of boys is equal to 1/7 of girls    (make the numer­a­tor common)

3/4 of boys is equal to 3/21 of girls

boys –> 4u

girls -> 21u

4u + 21u = 25u

25u –>  225 children

1u –>  9 children

4u –>  4 × 9 = 36 boys

Con­tinue read­ing