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CBSE · Class 7 · Mathematics

Finding the Unknown

Standard difficulty · 20 questions · 40 marks

Name: Date: Score: ____ / 40

Show your working for Sections B and C. Answers are on the last page — try every question first!

Section A — Choose the correct answer8 × 1 = 8 marks
1.
The solution of 7x + 17 = 38 is:
  1. x = 21
  2. x = 4
  3. x = 7 6/7
  4. x = 3
2.
"9 more than a number y is 20" as an equation is:
  1. y + 9 = 20
  2. 9y = 20
  3. y − 9 = 20
  4. y = 20 + 9
3.
Which value of x satisfies 3x − 2 = 13?
  1. 4
  2. 15
  3. 6
  4. 5
4.
If x/16 = 0, then x = ?
  1. 1/16
  2. 16
  3. 1
  4. 0
5.
Transposing +7 from the LHS to the RHS of an equation makes it:
  1. −7 on the RHS
  2. × 7 on the RHS
  3. ÷ 7 on the RHS
  4. +7 on the RHS
6.
If 2x = 57 − 7, then x = ?
  1. 32
  2. 25
  3. 50
  4. 24
7.
If 8(x − 1) = 48, then x = ?
  1. 56
  2. 6
  3. 8
  4. 7
8.
Which of these is an equation?
  1. 6x
  2. 6x + 8
  3. 6x + 8 = 20
  4. 6x + 8 > 20
Section B — Short answer8 × 2 = 16 marks
9.
Solve: 9x − 14 = 31
10.
Solve: 8x − 19 = −51
11.
Solve: 5(x + 2) = 60
12.
Solve: x/5 + 7 = 16
13.
Solve: 38 − 5y = 8
14.
Write an equation and solve: "Seven times a number decreased by 1 is 83."
15.
Check whether x = 4 is a solution of 3x + 1 = 16. Show your working.
16.
Solve: 2p + 24 = 46
Section C — Word problems4 × 4 = 16 marks
17.
The length of a rectangle is 5 cm more than its breadth. Its perimeter is 66 cm. Find the length and breadth.
18.
A father is 3 times as old as his son. The sum of their ages is 48 years. How old is the son?
19.
The sum of three consecutive whole numbers is 78. Find the numbers.
20.
Meera has Rs 27. Her mother gives her money to buy 8 notebooks, all at the same price. Now Meera has Rs 179. What is the price of one notebook?
AmbifulWorksheets
Practice that never repeats
CBSE · Class 7 · Mathematics

Answer key

Finding the Unknown · AW-7M-EQN-2026-V1 · For parents — fold back or tear off before handing the sheet to your child.

QAnswerWorking
1(d) x = 37x = 38 − 17 = 21, x = 3
2(a) y + 9 = 20—
3(d) 53 × 5 − 2 = 13
4(d) 00 × 16 = 0
5(a) −7 on the RHSa term changes sign when transposed
6(b) 252x = 50, x = 25
7(d) 7x − 1 = 6, x = 7
8(c) 6x + 8 = 20an equation has an equals sign with expressions on both sides
9x = 59x = 31 + 14 = 45; x = 45 ÷ 9 = 5
10x = −48x = −51 + 19 = −32; x = −32 ÷ 8 = −4
11x = 10x + 2 = 60 ÷ 5 = 12; x = 10
12x = 45x/5 = 9; x = 45
13y = 65y = 38 − 8 = 30; y = 6
147n − 1 = 83; n = 127n = 83 + 1 = 84; n = 12
15No3 × 4 + 1 = 13 ≠ 16 (the solution is x = 5)
16p = 112p = 22; p = 11
17breadth = 14 cm, length = 19 cm2(b + 5 + b) = 66 → 4b + 10 = 66 → 4b = 56 → b = 14
1812 years (father 36 years)x + 3x = 48 → 4x = 48 → x = 12
1925, 26, 27n + (n + 1) + (n + 2) = 78 → 3n + 3 = 78 → n = 25
20Rs 1927 + 8x = 179 → 8x = 152 → x = 19