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Logic puzzles
Textbook: Part 2, pp. 70–71
GoalLogic puzzles: finding patterns, ordering and reasoning puzzles.
New words
logic · mantiqpattern, rule · qonuniyatthe next number · keyingi sonorder · tartib
Explanation
In a logic puzzle you need to think before you calculate. To find a pattern in a row of numbers, look at the differences between neighbours: in 1, 3, 6, 10, 15 the differences are 2, 3, 4, 5, so the next difference is 6 and the next number is 21. In order puzzles watch the words “before” and “after” and draw a quick sketch.
Worked examples
In the row 2, 4, 7, 11, 16 the differences are 2, 3, 4, 5, so the next number is 16 + 6 = 22.
A gardener had 12 trees and all but five dried up. Five trees did not dry up.
Class activity
“Puzzle stop”: each group gets one logic puzzle. The group explains its solution with a sketch or table. The clearest explanation earns a star.
Practice
1
Continue: 5, 6, 8, 11, 15, ... What is the next number?
20
2
Dilnoza came before Aziza, and Aziza came before Madina. Who came first?
Dilnoza
3
A gardener had 12 trees and all but five dried up. How many did not dry up?
5
4
Lunch has 2 soups (mastava, laghman) and 3 main dishes. With each soup there are 3 choices. How many different lunches are there?
6