64
Adding two-digit numbers by place value
Textbook Part 2, pp. 48–49
GoalAdd by splitting numbers into tens and ones, and compare results.
New words
tens (short) · o‘nl.ones (short) · birl.lamp · chiroq
Explanation
Split numbers into places: 73 = 7 tens 3 ones. For 45 + 12: 4 tens + 1 ten = 5 tens, 5 ones + 2 ones = 7 ones → 57. Writing it this way stops the digits getting mixed up.
Worked examples
Class 1A has 10 lamps, 1B also 10, and 1D 11: 10 + 10 + 11 = 31.
16 + 52 = 68; 81 + 14 = 95
Class activity
Table: “number | tens | ones”. The teacher says a number, children fill in the table on the board, then add two rows.
Practice
1
28 + 11 = ?
39
2
45 + 12 = ?
57
3
Split into places: 86
8 tens 6 ones
4
Put the sign: 16 + 23 ... 33 + 2
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