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Solving word problems
Textbook: Part 3, lesson 116, pp. 94–95
GoalSolve multiplication and division problems with expressions; find area and an unknown side.
New words
word problem · masalaexpression · ifodachart, diagram · diagrammaequally · baravar
Explanation
To solve a problem we first read it and find what is known and what is asked. Then we choose the operation: “in each” – multiply, “shared equally” – divide, “in total” – add. We write an expression, calculate and check the answer. If the area of a rectangle is S = a × b, the unknown side = S : the known side.
Worked examples
2 buses with 35 people each: 35 × 2 = 70 people.
40 classmates in cabins for 4 people: 40 : 4 = 10 cabins.
Class activity
“Problem makers”: in pairs, children make up problems for each other (shop, trip, garden); the partner writes the expression, solves it and checks the answer.
Practice
1
Two buses set off to the mountains with 35 people on each. How many people in total?
70
2
40 classmates ride a Ferris wheel. 4 people fit in one cabin. How many cabins are used?
10
3
One ride costs 3 thousand so‘m. Laziz took 7 rides. How many thousand so‘m did he spend?
21
4
(6 × 9) + 46 = ?
100
5
A rectangle has area 48 dm² and length 6 dm. How many dm is its width?
8
6
Solve: 45 : x = 9. x = ?
5