63
Adding two-digit numbers
Textbook Part 2, pp. 46–47
GoalAdd ones to ones and tens to tens (no regrouping).
New words
ones with ones · birliklarga birliktens with tens · o‘nliklarga o‘nlikgram · gramm
Explanation
To add two-digit numbers, add the ones to the ones and the tens to the tens. 34 + 25: tens 30 + 20 = 50, ones 4 + 5 = 9 → 59.
Worked examples
Mum added 40 g salt, 30 g sugar and 12 g citric acid to water: 40 + 30 + 12 = 82 g.
11 litres of light-blue and 14 litres of yellow paint were mixed: 11 + 14 = 25 litres of green paint.
Class activity
Each pair builds two numbers with ten-bundles and sticks, puts all the bundles together and all the sticks together, and reads the sum.
Practice
1
23 + 45 = ?
68
2
51 + 36 = ?
87
3
40 + 27 = ?
67
4
A box has 32 big nails and 15 small ones. How many in all?
47