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Challenge problems
Textbook Part 3, pp. 50–51
GoalSolve logic problems about days of the week, order and prices.
New words
yesterday · kechatoday · buguntomorrow · ertagaprice · narx
Explanation
To solve a logic problem, check the facts one at a time, starting with the most definite one. In day-of-the-week problems, find “today” first, then count back or forward.
Worked examples
Yesterday was Lola’s birthday. Tomorrow is Friday. So today is Thursday, and her birthday was Wednesday.
Prices are 5, 10 and 12 thousand som. Chocolate costs more than ice cream but less than samsa → ice cream 5, chocolate 10, samsa 12 thousand.
Class activity
“Who sits where?” game: 3 children and 3 chairs. The teacher gives clues (“Ali is not at the end”, “Vali is left of Ali”). The class seats them correctly.
Practice
1
Tomorrow is Monday. What day was yesterday?
Saturday
2
Each day Aziz read 1 page more than the day before. In 4 days he read 10 pages. How many each day?
1, 2, 3, 4
3
Put “+” or “−”: 9 ... 4 ... 3 = 8
9 − 4 + 3 = 8
4
Write the next two numbers: 2, 5, 8, 11, _, _
14, 17