Cogito
Grade 3 Math · Chapter 7 · Lesson 3
Two-Step Problems With All Four Operations
Working out which operations, and in what order.
10 problems · about 15 minutes · 3.OA.D.8
What this lesson teaches
The child solves two-step word problems using any of the four operations.
- A two-step problem hides a first question.
- Multiplication and division usually come first.
- Estimate before you start, and check at the end.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
1 problemReview — Equal Areas of a Shape: A shape split into 7 equal parts. What is the denominator of one part?
Answer 7
Why Each part is 1/7 of the shape.
Warm Up
Straightforward practice. Get the method working first.
4 problems9 × 6 − 20 = ?
Answer 34
Why 9 × 6 = 54, and 54 − 20 = 34.
What should you do before working a two-step problem?
Answer Estimate, so a wrong answer stands out.
Why An estimate gives you something to judge the answer against.
7 × 6 − 15 = ?
Answer 27
Why 42 − 15.
54 ÷ 9 + 12 = ?
Answer 18
Why 6 + 12.
Build It Up
The same ideas with more to keep track of.
2 problems8 × 7 − 26 = ?
Answer 30
Why 56 − 26.
63 ÷ 7 + 25 = ?
Answer 34
Why 9 + 25.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
3 problemsThe Sweet Shop: 4 bags of 9 sweets. 12 are eaten. How many are left?
Answer 24 sweets
Why 36 − 12 = 24.
The Class Trip: 48 children go in groups of 6. Then 2 more groups join. How many groups in all?
Answer 10 groups
Why 8 + 2 = 10 groups.
The Bookshelf: 35 books are shared onto 5 shelves. Then 4 more go on one shelf. How many on that shelf?
Answer 11 books
Why 7 + 4 = 11 books.