☰ Contents · Mathematics

Adding up to a round number and subtracting from a round number

Lessons 11–15 · 5 lessons · I.V. Repyova, Y.V. Zemlina. Mathematics Grade 2, Parts 1–4. Novda Edutainment, 2023
14

Subtracting (30 − 7)

Textbook: Part 1, lesson 14, pp. 30–31
GoalLearn the method for subtracting ones from a ten (30 − 7).
New words
calendar · taqvimweek · haftaday · kunsubtracting from tens · o‘nlikdan ayirish
Explanation

We calculate 30 − 7 like this: 30 = 20 + 10. First 10 − 7 = 3. Then add it to 20: 20 + 3 = 23. There are 7 days in a week.

Worked examples
60 − 1 = 50 + (10 − 1) = 50 + 9 = 59.
30 − 9 = 20 + (10 − 9) = 21; 80 − 3 = 77.
Class activity

“With the calendar”: choose a date on the class calendar. Children find the date a week earlier and a week later (subtract and add 7).

Practice
1
20 − 7 = ?
2
70 − 9 = ?
3
How many days are in one week?
4
A shop had (40 + 50) kg of apples. 8 kg were sold. How many kg are left?