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Class 8 Algebra Play worksheet
CBSE Mathematics. Number tricks explained with algebra, the 1089 trick, reversed digits, calendar squares, nth terms. Every sheet has 20 questions in three sections and an answer key, and the numbers change every time.
Sample questions
Real questions from this chapter, as the app sets them. Tap Answer to see the answer and working.
Section A · multiple choice
- 1.
Think of a number. Multiply it by 2, add 14, divide by 2, then subtract the number you thought of. The answer is always:
- 2
- 14
- your number
- 7
Answer
(d) 7
(2n + 14) ÷ 2 − n = 7
- 2.
997 − 799 equals 99 times:
- 16
- 7
- 2
- 9
Answer
(c) 2
198 = 99 × 2
- 3.
Think of a number, add 4, double it, subtract 8, and halve it. You get:
- 8
- double your number
- 4
- the number you thought of
Answer
(d) the number you thought of
(2(n + 4) − 8) ÷ 2 = n
Section B · short answer
- 4.
Think of a number n. Add 13, multiply by 5, subtract 65. Write the result in terms of n, and find it for n = 30.
Answer
5n; 150
5(n + 13) − 65 = 5n
- 5.
Try the 1089 trick with 793: reverse it and subtract the smaller from the larger, then reverse the answer and add. What do you get?
Answer
1089
793 − 397 = 396; 396 + 693 = 1089
Section C · long answer
- 6.
Ananya says: "Think of a number, double it, add 4, halve it, and take away the number you first thought of. I know your answer!" What is the answer, and why?
Answer
2, whatever the number
(2n + 4) ÷ 2 − n = 2
Fresh sheets for your child
In the app, every Algebra Play sheet is new: the app remembers the questions your child has already had and leaves them out. Print the sheet as a PDF, or use notebook mode and write the answers in a notebook.
Coming soon for Android and iPhone.