Singapore Math Level 2A & 2B – Challenge Questions Of 2B - 12 Questions
CHALLENGE QUESTIONS OF 2B
Solve the following problems of question no 1-12.
1. The chart below shows the number of pieces of clothing Mrs. Robinson sewed.
Number of days | 1 | 3 | 6 |
Pieces of clothing | 4 | 12 | 24 |
How many pieces of clothing did Mrs. Robinson sew in 10 days?
Solution(1):
1 day → 4 pieces of clothing
10 days → 10 × 4 = 40 pieces of clothing
Mrs. Robinson sewed 40 pieces of clothing in 10 days.
2. Sarah is 12 years old. Hes mother is 3 times her age. Her father is 5 years older than her mother. How much older is Sarah’s father than Sarah?
Solution(2):
Sarah → 12
Mother → 12 × 3 = 36
Father → 36 + 5 = 41
So, Father – Sarah
= 41 – 12
= (41-10) – 2
= 31 – 2
= 29
Sarah’s father is 29 years older than Sarah.
3. Use numbers from 10 to 18 to make each vertical and horizontal line equal to the numbers in the shaded boxes. Each number can be used only once.
41 | |||
42 | |||
43 | |||
43 | 42 | 41 |
Solution(3):
18 | 10 | 13 | 41 |
11 | 15 | 16 | 42 |
14 | 17 | 12 | 43 |
43 | 42 | 41 |
4. Five minutes before recess, Carlos and Henry looked at their watches. Carlos’s watch was 5 minutes faster than the classroom clock. Henry’s watch was 5 minutes slower than the classroom clock. If Carlos’s watch showed 9:50 A.M., what was the time shown on Henry’s watch?
Solution(4):
Carlos’s watch → 9:50 A.M.
Classroom clock → 9:50 A.M – 5 minutes = 9:45 AM
Henry’s watch → 9:45 A.M – 5 minutes = 9:40 AM
The time shown on Henry’s watch was 9:40 A.M.
5.
♥ + △ = 120
♥ + ♥ = 80
♥ + △ + △ + △ = _____
Solution(5):
♥ + ♥ = 80
2♥ = 80
♥ = 80 ÷ 2 = 40
Now,
♥ + △ = 120
40 + △ = 120
△ = 120 – 40 = 80
So,
♥ + △ + △ + △ = 40 + 80 + 80 + 80 = 280
6. The product of 2 numbers is 50. The result of the division of the 2 numbers is 2. What are the 2 numbers?
Solution(6):
Use the guess-and-check method.
Guess 1: 1 × 50 = 50;
Guess 2: 2 × 25 = 50
Guess 3: 5 × 10 = 50
In Guess 3: 10 ÷ 5 = 2
The 2 numbers are 5 and 10.
7. Christopher had a bottle of orange juice. He gave some juice to his best friend. He then gave half of the the remaining juice to his neighbor. He was left with ¼ of the bottle of orange juice. What fraction of the bottle of orange juice did Christopher give to his best friend?
Solution(7):
Since ¼ of the bottle of orange juice was left, the amount of juice Christopher gave to his neighbor was also ¼.
1 – ¼ – ¼
= 4/4 – ¼ – ¼
= 2/4
= ½
Christopher gave his best friend ½ of the bottle of orange juice.
8. Austin spent an hour watching cartoons followed by 2 hours of a nap, and 3 hours of homework. If Austin completed his homework at 10 P.M., what time did he start watching cartoons?
Solution(8):
1 + 2 + 3 = 6 hr.
6 hr. before 10 PM is 4 PM.
He started watching cartoons at 4 PM.
9. How many triangles are there in the figure shown below? (Hint: The triangles do not need to all be the same size.)
Solution(9):
There are 26 triangles in the figure.
The total no of triangles are calculated as per the following process:
10. Fill in the blank by using guess-and-check method.
☾× ◇ = 32 ☾+ ◇ = 12
☾÷ ◇ = 2 ☾- ◇ = _____
Solution(10):
Use the guess-and-check method.
8 × 4 = 32
8 ÷ 4 = 2
8 + 4 = 12
☾– ◇ = 8 – 4 = 4
11. Winnie uses some sticks to form 2 squares as shown below. How would you rearrange 4 matchsticks to form 3 rectangles?
Solution(11):
The rearrange process are shown below:
12. It took Mrs Sofia 30 minutes to wash her car and an hour to mow the lawn. Then, she took a 20-minute bath. By the time she stepped out of the bathroom, the hour hand pointed to 1 and the minute hand pointed to 4. On the clock, show the time Mrs Sofia started to wash her car.
Solution(12):
Mrs Sofia stepped out of the bathroom at 1:20 P.M.
30 min. + 1 hr. + 20 min. = 1 hr. 50 min.
1 hr. 50 min. before 1:20 P.M. is 11:30 A.M.
Also: