97
Two-step word problems
Textbook Part 3, pp. 48–49
GoalPlan and solve problems that take two steps.
New words
two-step problem · ikki amalli masalafirst … then … · avval … keyin …ribbon · lenta
Explanation
In some problems you cannot answer the question at once — first find a helper number. “Lola sewed 12 dresses and Komila 2 more. How many in all?” 1) Komila: 12 + 2 = 14; 2) total: 12 + 14 = 26. As one expression: 12 + (12 + 2) = 26.
Worked examples
A box had 25 buttons; 10 were added, then 13 used: 25 + 10 − 13 = 22.
Malika has 3 ribbons of different colours; choosing 2: RY, RB, YB — 3 ways.
Class activity
Sorting buttons: children group buttons by colour, then by number of holes, and write an expression for each grouping.
Practice
1
Lola sewed 12 dresses and Komila 2 more. How many in all?
26
2
A class has 15 girls and 3 fewer boys. How many pupils in all?
27
3
25 + 10 − 13 = ?
22
4
Thread the buttons whose value is 13: 6 + 7, 9 + 5, 20 − 7, 8 + 5
6 + 7, 20 − 7, 8 + 5