61
Reading and writing 21–100 (abacus)
Textbook Part 2, pp. 42–43
GoalShow and read two-digit numbers on an abacus; logic puzzles with tens and ones.
New words
abacus · cho‘twire / rod · simbead · toshchasum of the digits · raqamlar yig‘indisi
Explanation
A frame with beads on wires is called an abacus. Beads on the lowest wire show ones, the next wire shows tens. 6 ten-beads and 3 one-beads make 63.
Worked examples
Aziz thought of a number: 6 tens, and 3 fewer ones than tens. The number is 63.
Each stack has 10 plates. 4 stacks and 7 single plates make 47.
Class activity
If there is no abacus, use two rows of buttons: a child shows the teacher’s number by putting buttons in the tens row and the ones row.
Practice
1
On the abacus: 8 tens, 2 ones. Which number?
82
2
Write the two-digit numbers whose digits add up to 5.
14, 23, 32, 41, 50
3
70 + 6 = ?
76
4
The lower shelf has 3 stacks and 5 plates, the upper shelf 2 stacks. How many plates in all?
55