43
Tens and ones in 11–20
Textbook Part 2, pp. 6–7
GoalUnderstand what each digit in a two-digit number means; write a number as tens plus ones.
New words
place (value) · xonatens place · o‘nliklar xonasiones place · birliklar xonasiexpanded form · xona qo‘shiluvchilari
Explanation
A two-digit number is written with two digits. The first digit tells how many tens; the second tells how many ones. In 14: 1 means one ten, 4 means four ones. So 14 = 10 + 4. The position of a digit in a number is called its place.
Worked examples
18 = 10 + 8; 20 = 10 + 10
Alisher walked 10 minutes to the crossroads, then 8 minutes to school: 10 + 8 = 18 minutes.
Class activity
“Place-value house”: a house with two rooms on the board — “tens | ones”. The teacher says a number and a child writes the digits in the right rooms.
Practice
1
Write as tens plus ones: 16
10 + 6
2
Write as tens plus ones: 11
10 + 1
3
10 + 9 = ?
19
4
How many ones are in 13?
3