Cogito
Grade 1 Math · Chapter 10 · Lesson 9
Tricky Comparison Problems
Some problems try to lead you the wrong way.
10 problems · about 14 minutes · 1.OA.A.1
What this lesson teaches
The child solves compare problems with the bigger or smaller quantity unknown, including versions whose wording suggests the wrong operation.
- A word in the problem is not the answer.
- Draw the two bars first.
- The picture shows you what to do.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
3 problemsReview — When You Need a New Ten: 29 + 34 = ?
Answer 63
Why 5 tens and 13 ones becomes 6 tens and 3 ones.
Review — Adding to 100 With Place Value: 34 + 25 = ?
Answer 59
Why 5 tens and 9 ones is 59.
Review — Ten More, Ten Less to 100: Ten more than 66 is?
Answer 76
Why 6 tens became 7 tens.
Warm Up
Straightforward practice. Get the method working first.
3 problemsAna has 3 more than Leo. Ana has 10. Leo has?
Answer 7
Why 10 − 3 = 7.
Does the word "more" always mean add?
Answer No. Draw it and see.
Why The picture decides, not the word.
6 more than Leo. Ana has 14. Leo has?
Answer 8
Why Leo has fewer.
Build It Up
The same ideas with more to keep track of.
1 problem5 fewer than Ana. Leo has 9. Ana has?
Answer 14
Why Ana has more.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
3 problems2 more than Leo. Ana has 13. Leo has?
Answer 11
Why 13 take away 2.
Marbles: Ana has 4 more than Leo. Ana has 15. How many does Leo have?
Answer 11 marbles
Why Leo has 15 − 4 = 11.
Books: Leo has 3 fewer than Ana. Leo has 8. How many does Ana have?
Answer 11 books
Why Ana has 8 + 3 = 11.