Singapore Math Level 3A & 3B – Review 4: Multiplying, Dividing And Mental Calculations - 40 Questions
REVIEW 4: MULTIPLYING, DIVIDING AND MENTAL CALCULATIONS
Singapore Math Level 3A & 3B – Review 4: Multiplying, Dividing, and Mental Calculations contains a total of 40 questions, and their solutions are provided here. It is worth noting that not all questions are presented exactly as they are; some are presented in a slightly different but equivalent manner, although all solutions follow the same rules as the exact questions in the textbook.
Solve the following division problems. Show your work.
1. 7)537 2. 6)612 3. 9)908 4. 4)504
Solution(1-4):
1.
7)537
49
47
42
5
∵ Quotient: 76; Remainder: 5
2.
6)612
6
1
0
12
12
0
∵ Quotient: 102
3.
9)908
9
0
0
8
0
8
∵ Quotient: 100; Remainder: 8
4.
4)504
4
10
8
24
24
0
∵ Quotient: 126
5. Find the smallest 4-digit even number using the digits 3, 5, 2, and 8.
Solution(6):
2 < 3 < 5 < 8
So, the smallest 4-digit number is 2358, and it is an even number.
6. Find the largest 4-digit odd number using the digits 4, 8, 9, and 3.
Solution(6):
9 > 8 > 4 > 3
So, the largest 4-digit number is 9843, and it is an odd number.
7. Solve the following problems to find out where Nick is going.
I: 7)357 R: 4)824 B: 3)954 A: 5)675 Y: 6)714 L: 9)711
79 51 318 206 135 206 119
Solution(7):
The solution is shown in the figure below:
8. Divide 278 by 2 to find the quotient.
Solution(8):
2)278
2
7
6
18
18
0
∵ Quotient: 139
9. Add 37 and 69 mentally.
Solution(9):
37 + 69
= 37 + 70 – 1
= 107 – 1
= 106 (Ans.)
10. Write all the odd numbers from 51 to 61.
Solution(10):
51, 53, 55, 57, 59, 61.
11. Subtract 19 from 34 mentally.
Solution(11):
34 – 19
= 34 – 20 + 1
= 14 + 1
= 15 (Ans.)
12. Divide 400 by 8 to find the quotient.
Solution(12):
8)400
40
0
0
0
∵ Quotient: 50
13. Write all the even numbers from 30 to 40.
Answer: 32, 34, 36, 38, 40.
14. Calculate manually: the product of 8 and 5
Answer: 8x5 = 40
15. Divide 24 by 6 to find the quotient.
Solution(15):
6)24
24
-----------
0
∵Quotient: 4
16. Anya buys 4 bags of biscuits. There are 5 packets of biscuits in each bag.
(a) How many packets of biscuits are there altogether?
(b) Anya gives all the packets of biscuits to her classmates. If each of her friends receives 2 packets of biscuits, how many classmates does she give the biscuits to?
Solution(16):
(a)
4 × 5 = 20
There are 20 packets of biscuits altogether.
(b)
20 ÷ 2 = 10
She gives the biscuits to 10 classmates.
17. Serena has 6 boxes of stickers. There are 230 stickers in each box. She gives the stickers to her 3 friends. How many stickers does each friend receive?
Solution(17):
230 × 6 = 1380
× 6
1380
There are 1380 stickers altogether.
1380 ÷ 3 = 460
3)1380
12
18
18
0
0
0
Each friend receives 460 stickers.
18. Rashid uses 8 packets of sugar to make 2 cakes. Each packet of sugar has a mass of 50 gram. How much sugar does she need for each cake?
Solution(18):
50 × 4 = 200
She needs 200 g of sugar for each cake.
19. Shop X sells 3 dolls for $27. Shop Y sells the same toys at 5 for $40. If Alex wants to buy only 1 doll, which shop sells the doll at a cheaper price?
Solution(19):
$27 ÷ 3 = $9
$40 ÷ 5 = $8
Shop Y sells the doll at a cheaper price.
20. Joseph travels a total of 464 yards from his flat to his office and back to his flat.
(a) How far is Joseph’s flat from the office?
(b) How far would Joseph travel in 5 days if he were to travel from his flat to the office and back to his flat?
Solution(20):
(a)
464 ÷ 2 = 232
2)464
4
6
6
4
4
0
Joseph’s house is 232 yd. from the office.
(b)
464 × 5 = 2320
Joseph would travel 2320 yd. in 5 days.
Also: