fractions revision solutions - jimmy maths
TRANSCRIPT
www.jimmymaths.com
1
Fractions Revision – Solutions
Section A
For each question, four options are given. One of them is the correct answer. Make your choice (1, 2, 3 or 4) and write your answer in the brackets.
1. 3 boys shared half a pizza equally. What fraction of the original pizza did each boy receive?
(1) (2) (3) (4)
Fraction each boy received = ÷ 3
=
=
Ans: (4)
2. 900 + + = __________
(1) 900.99 (2) 901.89 (3) 909.99 (4) 990.89
900 + + = 900 + 0.9 + 0.99
= 901.89
Ans: (2)
3. What is the value of – ?
(1) (2) (3) (4) 1
– = –
=
Ans: (3)
www.jimmymaths.com
2
4. After Mei Mei gave away of her stamps and Wan Xi gave away of her stamps,
they had the same number of stamps left. They had 312 stamps left. How many stamps they have altogether at first?
(1) 600 (2) 624 (3) 676 (4) 728
Number of stamps each girl had left = 312 ÷ 2
= 156
of Mei Mei’s stamps = 156
of Mei Mei’s stamps = 156 ÷ 3
= 52
of Mei Mei’s stamps = 7 52
= 364
Number of stamps Mei Mei had at first = 364
of Wan Xi’s stamps = 156
of Wan Xi’s stamps = 2 156
= 312
Number of stamps Wan Xi had at first = 312
Number of stamps they had altogether at first = 364 + 312
= 676
Ans: (4)
www.jimmymaths.com
3
5. Arrange the following fractions in descending order.
, , 1
(1) , 1 , (2) , 1 , (3) 1 , , (4) , , 1
= 1
Smallest fraction =
Compare 1 and 1 .
=
=
Largest fraction = 1
In descending order: 1 , ,
Ans: (3)
6. How many tenths are there in 1 ?
(1) 14 (2) 12 (3) 7 (4) 4
1 =
=
= 14
Number of tenths = 14
Ans: (1)
www.jimmymaths.com
4
7. of a number is 27. What is of the number?
(1) 243 (2) 54 (3) 3 (4) 6
of the number = 27
of the number = 2 27
= 54
of the number = 54
= 6
Ans: (4)
8. How many are there in the number statement below so that the statement is true?
÷ ÷ ÷ … … ÷ = 16
(1) 7 (2) 6 (3) 5 (4) 4
÷ = 2 = 1
1 ÷ = 1 2 = 2
2 ÷ = 2 2 = 4
4 ÷ = 4 2 = 8
8 ÷ = 8 2 = 16
Number of = 6
Ans: (2)
www.jimmymaths.com
5
9. Which of the following fractions is closest to ?
(1) (2) (3) (4)
Tip: Change all the fractions to decimals.
= = 0.6
= 0.666… (Difference = 0.066…)
= 0.7 (Difference = 0.1)
= = 0.55 (Difference = 0.05)
= = 0.68 (Difference = 0.08)
Ans: (3)
www.jimmymaths.com
6
10. The figure is made up of three equilateral triangles ADC, ABD and BED.
What fraction of the Figure ABEC is shaded?
(1) (2) (3) (4)
Notice that in Triangle ACD, of the triangle is shaded.
Similarly in Triangle ABD, of the triangle is shaded.
Therefore 2 out of 6 parts of Figure ABEC is shaded.
Fraction of Figure ABEC shaded =
=
Ans: (2)
www.jimmymaths.com
7
Section B
Questions 11 to 15 carry 1 mark each. Questions 16 to 20 carry 2 marks each. Show your working clearly and write your answers in the spaces provided. For questions which require units, give your answers in the units provided.
11. Write down the fraction exactly between and .
Method 1: Calculation
Difference between the two fractions = –
= –
=
Divide the difference into 2 = ÷ 2
=
=
Fraction exactly in between = –
= –
=
= (Ans)
Method 2: Observation
=
Find the fraction between and .
Continue using equivalent fractions:
=
=
Fraction exactly in between = = (Ans)
www.jimmymaths.com
8
12. How many minutes are there in 4 h?
Number of minutes = 4 60
= 60
= 260 (Ans)
13. of a number is 81. What is of the number?
of the number = 81
of the number = 81 ÷ 3
= 27
of the number = 7 27
= 189
of the number = 189
= 42 (Ans)
www.jimmymaths.com
9
14. In the number line below, BC is of AB. What is the fraction represented by B?
Difference between and = –
= –
=
3 units =
1 unit =
B = –
=
= (Ans)
15. Express as a decimal, correct to 2 decimal places.
= 6 ÷ 7
= 0.857…
= 0.86 (2 decimal places) (Ans)
www.jimmymaths.com
10
16. Peter has as many books as Kate. Cindy has as many books as Peter. Cindy has
96 books, how many books does Kate have?
Peter : Kate : Cindy
2 5 : 3 5
5 2 : 4 2
10 : 15 : 8
8 units = 96
1 unit = 96 ÷ 8
= 12
15 units = 15 12
= 180
Number of books Kate has = 180 (Ans)
17. Joe had as much money as Hope at first. After both of them received $27 each,
Joe had as much money as Hope. How much money did both of them have at first?
Joe : Hope Difference
Before 3 : 5 2
After 3 2 : 4 2 1 2
6 : 8 2
(6 – 3 =) 3 units = $27
1 unit = $27 ÷ 3
= $9
(3 + 5 =) 8 units = 8 $9
= $72
Amount of money both of them had at first = $72 (Ans)
www.jimmymaths.com
11
18. The mass of a bottle completely filled with sand was 3 kg. After of the sand was
poured away, the mass of the bottle containing the remaining sand was 900 g. What
was the mass of the bottle, in grams, when it was empty?
Mass of of the sand = 3000 – 900
= 2100 g
Mass of of the sand = 2100 ÷ 3
= 700 g
Mass of the empty bottle = 900 – 700
= 200 g (Ans)
19. In the figure, ABCD is a rectangle. X and Y are midpoints of BC and DC. What fraction of the figure is the shaded triangle?
Area ADY = of ABCD
Area ABX = of ABCD
Area XCY = of ABCD
Fraction of the figure that is the shaded triangle = 1 – – –
= – – –
= (Ans)
www.jimmymaths.com
12
20. Julianna had a sum of money. After spending of it on a dress and of the
remainder on a book, she had $8 left. How much money did Julianna have at first?
of the remainder = $8
of the remainder = 6 $8
= $48
Remaining amount of money = $48
of the original sum of money = $48
of the original sum of money = $48 ÷ 3
= $16
of the original sum of money = 5 $16
= $80
Amount of money Julianna had at first = $80 (Ans)
www.jimmymaths.com
13
Section C
Show your working clearly and write your answers in the spaces provided. The number of marks is shown in brackets [ ] at the end of each question or part-question.
21. William had $108 more than Samuel. After William spent of his money and Samuel
spent half of his, both boys had a total of $102 left. How much money did each of
them have at first?
3 units + $27 = $102
3 units = $102 – $27
= $75
1 unit = $75 ÷ 3
= $25
4 units = 4 $25
= $100
Amount of money William had at first = $100 + $108
= $208 (Ans)
Amount of money Samuel had at first = $100 (Ans)
www.jimmymaths.com
14
22. There are 64 more boys than girls in an auditorium. of the girls and of the boys
wore spectacles. A same number of boys and girls wore spectacles. How many boys
and girls wore spectacles altogether?
Fraction of girls who wore spectacles =
Fraction of boys who wore spectacles = =
Girls ⟶ 3 units
Boys ⟶ 4 units
(4 – 3 =) 1 unit = 64
4 units = 4 64
= 256
Number of boys and girls who wore spectacles altogether = 256 (Ans)
www.jimmymaths.com
15
23. In a bookstore, the cost of a magazine is of the cost of a book. Peter used of his
money to buy 8 magazines and 13 books. How many books could he buy with of
his money?
Cost of 1 magazine = 5 units
Cost of 1 book = 8 units
Cost of 8 magazines and 13 books = 8 5 + 13 8
= 40 + 104
= 144 units
of his money = 144 units
of his money = 144 ÷ 2
= 72 units
of his money = 5 72
= 360 units
Number of books he could buy = 360 ÷ 8
= 45 (Ans)
www.jimmymaths.com
16
24. Dylan has 340 square and round stickers altogether. of his square stickers is 28
more than of his round stickers. How many square stickers and how many round
stickers does Dylan have?
9 units = 340 – 26 – 26
= 288
1 unit = 288 ÷ 9
= 32
4 units = 4 32
= 128
5 units = 5 32
= 160
Number of square stickers = 128 + 26 + 26
= 180 (Ans)
Number of round stickers = 160 (Ans)
www.jimmymaths.com
17
25. There were some pupils in a school canteen. The number of girls was of the
number of boys. After of the girls and of the boys left, there were 124 pupils
remaining in the canteen.
(a) What fraction of pupils left the canteen?
(b) How many pupils were there in the canteen at first?
(a) Girls : Boys
2 : 3
10 : 15 ⟵ Make the number of units for girls divisible by 5. However, the number of units for boys is not divisible by 2.
20 : 30 ⟵ Now, the number of units for girls is divisible by 5, and the number of units for boys is divisible by 2.
Number of girls who left the canteen = 20
= 4 units
Number of boys who left the canteen = 30
= 15 units
Fraction of pupils who left the canteen =
= (Ans)
(b) Number of girls remaining = 20 – 4
= 16 units
Number of boys remaining = 30 – 15
= 15 units
(16 + 15 =) 31 units = 124
1 unit = 124 ÷ 31
= 4
(20 + 30 =) 50 units = 50 4
= 200
Number of pupils in the canteen at first = 200 (Ans)
www.jimmymaths.com
18
26. Daisy had as much money as Leslie. Daisy received $220 from her mother and
Leslie spent $50. In the end, Daisy had twice as much money as Leslie. How much
money did Daisy have at first?
Daisy Leslie
Before 3 units 4 units
+ $220 – $50
After 2 parts 1 part
3 units + $220 = 2 parts
4 units – $50 = 1 part ⇒ 8 units – $100 = 2 parts
(8 – 3 =) 5 units = $220 + $100
= $320
1 unit = $320 ÷ 5
= $64
3 units = 3 $64
= $192
Amount of money Daisy had at first = $192 (Ans)
www.jimmymaths.com
19
27. Nicole, Pamela and Timmy shared a sack of rice. Nicole took of the rice and an
extra kg of the rice. Pamela took of the remaining rice and an extra kg of rice.
Timmy took the rest of the 13 kg of rice. What was the original mass of the sack of
rice the three of them shared?
Timmy’s share = 13 kg
Timmy and Pamela’s share = 2
= 27 kg
Nicole, Timmy and Pamela’s share = 2
= 55 kg
Original mass of the sack of rice = 55 kg (Ans)
www.jimmymaths.com
20
28. Ben had a sum of money. He spent of his money on a shirt, and of his money on
a bag. He then spent of the remainder on a pair of trousers and another $26 on a
belt. He had of his money left. How much did the shirt cost?
Fraction of money spent on the shirt and bag = +
= +
=
Remaining amount of money = 1 –
= –
=
Fraction of money spent on the pair of trousers =
=
Fraction of money spent on belt = 1 – – –
= – – –
=
=
of his money = $26
of his money = 4 $26
= $104
Cost of the shirt = $104 (Ans)
www.jimmymaths.com
21
29. There were 112 fewer Singapore stamps than Malaysia stamps in an album. Janet
gave away of the Singapore stamps and of the Malaysia stamps. The number of
Malaysia stamps left was twice as many as the number of Singapore stamps left.
How many stamps were there in the album at first?
Fraction of Singapore stamps left = 1 –
=
=
Fraction of Malaysia stamps left = 1 –
=
=
Singapore stamps ⟶ 20 units
Malaysia stamps ⟶ 48 stamps
(48 – 20 =) 28 units = 112
1 unit = 112 ÷ 28
= 4
(20 + 48 =) 68 units = 68 4
= 272
Number of stamps in the album at first = 272 (Ans)
www.jimmymaths.com
22
30. An MRT train departed from Jurong station. At Clementi station, of the passengers
alighted and 100 passengers boarded the train. At Woodlands station, of the
passengers alighted and 80 passengers boarded the train. There were 350
passengers on the train when it left Woodlands station. How many passengers were
there when the train departed from Jurong station?
On the train Alighted Boarded
Jurong station - - -
↓ ?
Clementi station 100
↓ ?
Woodlands station 80
350
Woodlands station
Number of passengers on the train after alighting and before boarding
= 350 – 80
= 270
of the passengers = 270
of the passengers = 270 ÷ 9
= 30
of the passengers = 10 30
= 300
Number of passengers on the train after leaving Clementi station = 300
www.jimmymaths.com
23
Clementi station
Number of passengers on the train after alighting and before boarding
= 300 – 100
= 200
of the passengers = 200
of the passengers = 200 ÷ 2
= 100
of the passengers = 5 100
= 500
Number of passengers on the train after leaving Jurong station = 500 (Ans)
END