Diagnostic

Math Diagnostic Test for 8th Grade

TypeDiagnostic
GradeGrade 8
SubjectMath
Duration55 min
Questions10
Rating★ 5

About this preparation

I want to create a diagnostic test in math for Jovan Ashan, 8th grade, for 55 minutes, at a medium difficulty level.

David Maina
Preparation author

Diagnostic tasks

Below is the full list of tasks with correct answers and explanations. In a lesson the tutor can hide the answers and reveal them after the student tries.

1
What is the value of -7 + 12?
-19
-5
5
19
Explanation: Adding 12 to -7 gives 5.
2
Which expression is equal to 3(2x - 5)?
6x - 15
6x - 5
3x - 15
5x - 6
Explanation: Distribute 3 to both terms: 3 × 2x = 6x and 3 × -5 = -15.
3
Solve for x: x + 9 = 17.
6
8
9
26
Explanation: Subtract 9 from both sides: x = 17 - 9 = 8.
4
A shirt costs $40 and is discounted by 15%. What is the sale price?
$6
$34
$35
$45
Explanation: 15% of 40 is 6, so the sale price is 40 - 6 = 34.
5
If 5 notebooks cost $12.50, how much do 8 notebooks cost at the same rate?
$15.00
$18.00
$20.00
$22.50
Explanation: One notebook costs $12.50 ÷ 5 = $2.50, so 8 notebooks cost 8 × $2.50 = $20.00.
6
Two angles of a triangle measure 48° and 67°. What is the measure of the third angle?
65°
75°
85°
95°
Explanation: The angles in a triangle add to 180°. 180 - 48 - 67 = 65.
7
What is the area of a rectangle with length 9 cm and width 4 cm?
13 cm²
18 cm²
36 cm²
40 cm²
Explanation: Area of a rectangle is length × width, so 9 × 4 = 36 cm².
8
Which number is a rational number?
√2
0.75
π
√5
Explanation: 0.75 can be written as the fraction 3/4, so it is rational.
9
Which of the following statements about a data set are true? Select all that apply.
The mean is found by adding all values and dividing by the number of values.
The median is always the largest value.
The mode is the value that appears most often.
The range is the difference between the greatest and least values.
Explanation: Mean, mode, and range are defined correctly in options a, c, and d.
10
Which of the following equations have x = 4 as a solution? Select all that apply.
x - 1 = 3
2x = 6
3x - 8 = 4
x + 5 = 10
Explanation: Substitute x = 4: a gives 3 = 3, c gives 12 - 8 = 4. The others are not true for x = 4.

Want the same result for your child?

We'll match a tutor to your child's age, level and goals. A first trial lesson — to get to know each other and build a plan.

Frequently asked questions

A diagnostic helps the tutor see the child's real level in 30–40 minutes: which topics are mastered and where the gaps are. Based on the result, the teacher builds an individual plan instead of working blind.

Yes, you can view all tasks and answers on this page. But the diagnostic is most useful in a lesson with a tutor who explains mistakes right away and adjusts the plan.

Roughly 30–40 minutes depending on the number of tasks and the child's pace. It is a full first lesson.