21
Adding (25 + 6)
Textbook: Part 1, lesson 20, pp. 44–45
GoalAdding with carrying by filling up to a whole ten (25 + 6).
New words
filling up to a ten · o‘nlikka to‘ldirishmetro (underground) · metrobus · avtobustransport · transport
Explanation
We split the second addend in two: the first part fills the first number up to a whole ten. 25 + 6 = (25 + 5) + 1 = 30 + 1 = 31. Splitting the addend like this prevents many mistakes.
Worked examples
38 + 5 = (38 + 2) + 3 = 40 + 3 = 43.
56 + 9 = (56 + 4) + 5 = 60 + 5 = 65.
Class activity
“Bus stops”: “stops” marked 10, 20, 30 ... lie on the floor. A child solves 27 + 6 by first walking to the nearest stop (30) and then taking the remaining steps.
Practice
1
27 + 4 = ?
31
2
56 + 9 = ?
65
3
42 + 9 = ?
51
4
In September Jasur rode the metro 8 times and the bus 25 times. How many rides in all?
33