28
Natural numbers
Textbook Part 1, pp. 58–59
GoalNumbers used for counting are natural numbers; tell one-digit from two-digit numbers.
New words
natural number · natural sonone-digit · bir xonalitwo-digit · ikki xonali
Explanation
The numbers we use to count objects are called natural numbers: 1, 2, 3, 4, ... 0 is not a natural number, because counting starts at 1. 1 to 9 are one-digit numbers (one digit); 10 is a two-digit number (two digits).
Worked examples
0, 3, 7, 10 → natural numbers: 3, 7, 10.
6 chairs at the table but only 4 plates. 2 more plates are needed: 6 − 4 = 2.
Class activity
The teacher calls out numbers. For a one-digit number children raise one hand, for two-digit both hands. For 0 they sit still.
Practice
1
Find the number that is not natural: 4, 0, 8, 1
0
2
Find the two-digit number: 9, 10, 5
10
3
What is the smallest natural number?
1
4
3 + 4 + 2 = ?
9