49
Comparing numbers to 20
Textbook Part 2, pp. 18–19
GoalCompare numbers using their tens and ones and their place on the number line.
New words
number line · sonlar qatorimore · ko‘proqfewer · kamroq
Explanation
If two numbers have the same tens (e.g. 17 and 13), compare the ones: 7 > 3, so 17 > 13. On the number line the number further right is bigger. A one-digit number is always smaller than a two-digit number: 9 < 11.
Worked examples
A white hen lays 17 eggs a month and a crested hen 13. 17 > 13, so breeding white hens gives more eggs.
A farmer bought 1 rooster, 9 speckled, 1 black and 8 white hens: 1 + 9 + 1 + 8 = 19. The coop holds 20, and 19 < 20 — no new coop needed.
Class activity
“Who’s bigger?” card game: in pairs, each child draws a card from 11–20; the bigger number wins a point and says the “>” sentence.
Practice
1
Put the sign: 14 ... 18
<
2
Put the sign: 19 ... 9
>
3
Put the sign: 10 + 6 ... 16
=
4
Write in increasing order: 17, 11, 20, 14
11, 14, 17, 20