Cogito
Grade 1 Math · Chapter 6 · Lesson 3
Putting Three in Order
Shortest, middle, longest.
10 problems · about 10 minutes · 1.MD.A.1
Figure — use these to answer the problems
Warm-Up Review
From earlier lessons. Loosen up before the new work.
5 problemsFrom “Using a Third Thing”
A rope is shorter than a string. The string is shorter than a pole. Is the rope shorter than the pole?
- Yes.
- No.
From “Longer Than, Shorter Than”
Why must you line up one end before comparing?
- Otherwise you cannot tell which is longer.
- To make it look neat.
From “True or False to Twenty”
Is 13 − 9 = 2 + 2 true?
- True. Both are 4.
- False.
From “Missing Numbers to Twenty”
8 + ? = 12
AnswerFrom “Take From Ten in Stories”
11 − 8 = ?
Answer
Warm Up
Straightforward practice. Get the method working first.
3 problemsRopes are 3, 9 and 6 cubes. How long is the longest?
AnswerHow much longer is a 9-cube rope than a 3-cube one?
AnswerSticks are 5, 8 and 2 cubes. How long is the longest?
Answer
Build It Up
The same ideas with more to keep track of.
1 problemStraws are 7, 4 and 6 cubes. How long is the shortest?
Answer
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
1 problemThree Ribbons
Ribbons are 6, 3 and 9 cubes long. How long is the shortest one?
Answercubes