Cogito
Grade 2 Math · Chapter 1 · Lesson 8
Two-Step Word Problems
Some problems need two answers before the real one.
10 problems · about 14 minutes · 2.OA.A.1
What this lesson teaches
The child solves two-step word problems within 20, identifying the hidden first question.
- Some problems hide a first question inside them.
- Work out the middle answer, then use it.
- The middle answer is never the answer.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
3 problemsReview — Choosing a Strategy: 9 + 7 = ?
Answer 16
Why 9 + 1 + 6 = 16.
Review — Find the Missing Number: ? + 8 = 15
Answer 7
Why 7 + 8 = 15.
Review — Addition and Subtraction Together: You know 8 + 5 = 13. What is 13 − 5?
Answer 8
Why 13 − 5 = 8, because 8 and 5 make 13.
Warm Up
Straightforward practice. Get the method working first.
3 problems9 sweets. 5 more given. 6 eaten. How many are left?
Answer 8
Why 9 + 5 = 14, and 14 − 6 = 8.
In a two-step problem, what is the first answer you find?
Answer A middle answer you still need to use.
Why The first answer feeds the second step.
7 apples. 6 more arrive. 4 are eaten. How many now?
Answer 9
Why 7 + 6 = 13 first.
Build It Up
The same ideas with more to keep track of.
1 problem15 birds. 7 fly away. 2 come back. How many now?
Answer 10
Why 15 − 7 = 8 first.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
3 problems5 red and 6 blue pens. 3 are lost. How many are left?
Answer 8
Why 5 + 6 = 11 first.
The Bakery: A tray held 8 buns. 6 more were baked. Then 5 were sold. How many buns are left?
Answer 9 buns
Why 8 + 6 = 14, and 14 − 5 = 9.
The Library: Leo borrowed 9 books and returned 4. Then he borrowed 3 more. How many does he have?
Answer 8 books
Why 9 − 4 = 5, and 5 + 3 = 8.