A thermometer reads 18 degrees Celsius in the morning and 31 degrees Celsius in the afternoon. By how many degrees did the temperature rise?
A. 13 degrees
B. 17 degrees
C. 23 degrees
D. 49 degrees
Show answer and reasoning
Correct answer: A. 13 degrees
Correct. 31 minus 18 = 13 degrees.
- B: 17 comes from a subtraction error (31 minus 14).
- C: 23 comes from subtracting 8 instead of 18.
- D: 49 is the sum, not the difference.
Source: CBEST Mathematics (096) Skill Factor 1: Estimation, Measurement, and Statistical Principles
A jug holds 1 gallon of water. A student pours out 3 quarts. How many quarts remain in the jug?
A. 1 quart
B. 2 quarts
C. 5 quarts
D. 13 quarts
Show answer and reasoning
Correct answer: A. 1 quart
Correct. A gallon is 4 quarts, and 4 minus 3 = 1 quart remains.
- B: 2 quarts would remain if a gallon were 5 quarts.
- C: 5 quarts is more than a full gallon.
- D: 13 treats a gallon as 16 quarts; 16 is the number of cups in a gallon.
Source: CBEST Mathematics (096) Skill Factor 1: Estimation, Measurement, and Statistical Principles
A restaurant bill is $47.60. Which is the best estimate of a 20 percent tip?
Show answer and reasoning
Correct answer: C. $10
Correct. Round the bill to $48; 10 percent is $4.80, so 20 percent is about $9.60, closest to $10.
- A: $5 is about 10 percent of the bill.
- B: $8 is about 17 percent.
- D: $12 is about 25 percent.
Source: CBEST Mathematics (096) Skill Factor 1: Estimation, Measurement, and Statistical Principles
A bookshelf is 36 inches wide. Each book is about 1.5 inches thick. About how many books will fit on one shelf?
Show answer and reasoning
Correct answer: B. 24
Correct. 36 divided by 1.5 = 24 books.
- A: 18 would be right if each book were 2 inches thick.
- C: 36 would be right only for books 1 inch thick.
- D: 54 is 36 x 1.5, a multiplication where division was needed.
Source: CBEST Mathematics (096) Skill Factor 1: Estimation, Measurement, and Statistical Principles
The number of books read by seven students over the summer were 3, 7, 2, 9, 4, 7, and 12. What is the median number of books?
Show answer and reasoning
Correct answer: B. 7
Correct. Ordered, the values are 2, 3, 4, 7, 7, 9, 12. The middle (fourth) value is 7.
- A: 6 is roughly the mean (44 divided by 7 is about 6.3), not the median.
- C: 9 is the fifth value in the ordered list, not the middle.
- D: 12 is the largest value.
Source: CBEST Mathematics (096) Skill Factor 1: Estimation, Measurement, and Statistical Principles
