Worksheets › Class 8 › We Distribute Yet Things Multiply: Thinking Puzzles
Class 8 · Computational Thinking and AI worksheetWe Distribute Yet Things Multiply: Thinking Puzzles
CBSE Computational Thinking and AI. The distributive law for mental maths, (a + b)(a − b), work schedules and train fares counted step by step, area models. Every sheet has 20 questions in three sections and an answer key, and the questions 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.
a × (b + c) equals:
- a + b × c
- (a × b) × c
- a × b + c
- a × b + a × c
Answer
(d) a × b + a × c
- 2.
Using the distributive law, 40 × 98 = ?
- 3,920
- 4,000
- 3,960
- 3,880
Answer
(a) 3,920
40 × (100 − 2) = 4,000 − 80
- 3.
104 × 96 = ?
- 10,000
- 9,996
- 10,016
- 9,984
Answer
(d) 9,984
(100 + 4)(100 − 4) = 100² − 4² = 10,000 − 16
Section B · short answer
- 4.
Explain why 25 × 44 = 25 × 40 + 25 × 4.
Answer
44 = 40 + 4, and multiplying a sum means multiplying each part and adding (the distributive law).
- 5.
Work out 66 × 9 using the distributive law.
Answer
594
66 × (10 − 1) = 660 − 66
Section C · long answer
- 6.
Painters A, B and C each paint 5 rooms on every day they work, on a 54-day job starting on a Monday. A does not work on Saturdays or Sundays; B does not work on every 6th day; C works every day. (a) On how many days does A work? (b) On how many days does B work? (c) How many rooms are painted altogether?
Answer
(a) 40; (b) 45; (c) 695
5 × (40 + 45 + 54) = 695
Fresh sheets for your child
In the app, every We Distribute Yet Things Multiply: Thinking Puzzles 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.