101
Dividing by 2
Textbook: Part 3, lesson 95, pp. 50–51
GoalSee how the quotient changes with the dividend and divisor; expressions and problems.
New words
dividend · bo‘linuvchidivisor · bo‘luvchiquotient · bo‘linmacomparison · taqqoslash
Explanation
The bigger the dividend, the bigger the quotient: 16 : 2 = 8 and 12 : 2 = 6, so 8 > 6. The bigger the divisor, the smaller the quotient: 12 clips shared between 2 friends give 6 each, shared between 6 friends give 2 each. In expressions with brackets we calculate inside the brackets first.
Worked examples
10 : 2 = 5 and 6 : 2 = 3, so 10 : 2 > 6 : 2.
(40 − 22) : 2: first 40 − 22 = 18, then 18 : 2 = 9.
Class activity
“Bigger or smaller?”: the teacher writes two divisions (for example 14 : 2 and 8 : 2). Children guess which quotient is bigger before calculating, then check.
Practice
1
Put a sign (<, > or =): 10 : 2 and 6 : 2
>
2
Calculate: (18 : 2) + 30 = ?
39
3
Calculate: (40 − 22) : 2 = ?
9
4
A book has 56 pages. 40 pages were read in the first week and the rest at 2 pages a day. In how many days was it finished?
8
5
I thought of a number and divided it by 2 to get 9. What was my number?
18