Ohio Grade 8 Achievement Test for Mathematics – May 2008
Annotated Item 7
Standard and Benchmark Assessed:
Standard:
Number, Number Sense and Operations
Benchmark:
G. Estimate, compute and solve problems involving real numbers, including
ratio, proportion and percents, amd explain solution
Multiple Choice Question:
7.
Mr. Bailey plans to plant soybeans in 4 of every 9 acres. This year, he plans to
farm 2,100 acres.
What is a reasonable estimate of the number of acres on which he will plant
soybeans?
A.
B.
C.
D.
60
230
520
930
Commentary:
This multiple-choice question asks students to solve a problem that require finding a reasonable
estimate for the number of acres on which soybeans will be planted using proportional
reasoning. Mr. Bailey planted soybeans in 4 out of every 9 acres, which was slightly less than
half of the area. Then he estimates that a little less than half of 2100 acres (about 1000)
represents the number of acres he plans to plant soybeans this year. Answer choice D, 930, is
correct because it is slightly less than 1000.
Students may also set up and then solve a proportion to find the number of acres, x,
x
4
=
2100
9
4  2100 = 9  x
933.33  x
933 = x
Students who choose answer choice A divided 2100 by 36 (9  4 = 36) and then rounded the
answer (2100  36  60).
Students who choose answer choice B divided 2100 by 9 and then rounded the answer (2100
 9 = 233.33  230).
Students who choose answer choice C divided 2100 by 4 and then rounded the answer
(2100  4 = 525  520).
Source: Ohio Department of Education
July 08
Ohio Grade 8 Achievement Test for Mathematics – May 2008
Annotated Item 7
The complexity level of this question is Moderate Complexity. This question requires students to
solve a word problem requiring multiple steps.
Performance Data:
The percent of public school students selecting answer choice D for question 7 on the May 2008
Grade 8 Achievement Test was 42%.
Keywords: number sense, proportional reasoning, estimation
Source: Ohio Department of Education
July 08