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Review: numbers, problems and equations
Textbook: Part 4, lesson 147, pp. 68–69
GoalYear review: comparing numbers, problems from diagrams, equations.
New words
comparing · taqqoslashascending order · o‘sish tartibidiagram · sxemaequation · tenglama
Explanation
To compare numbers, compare the hundreds first, then the tens, then the ones: 125 < 152 < 201 < 211 < 214 < 241. A diagram of a problem shows the known and unknown parts. In equations we use the opposite operation: x : 5 = 100, x = 100 × 5 = 500.
Worked examples
Of 75 pupils, 48 are in art and 15 in drama; the rest are 75 − 48 − 15 = 12.
600 : x = 60, x = 600 : 60 = 10.
Class activity
“Numbers line up”: six children hold cards 125, 152, 201, 211, 214, 241. The class helps them line up in ascending order, then re-arrange in descending order.
Practice
1
Write 214, 241, 201, 211, 125, 152 in ascending order.
125, 152, 201, 211, 214, 241
2
Of 75 second-grade pupils, 48 are in art club and 15 in drama club. The rest are in pottery. How many pupils are in pottery?
12
3
x : 5 = 100, x = ?
500
4
600 : x = 60, x = ?
10
5
x × 40 = 400, x = ?
10
6
A tailor has 38 m of green and 26 m of yellow cloth. 8 equal sheets were made from all of it. How many metres of cloth did one sheet take?
8