# CCSS strategies

Vocabulary:

Level 1 - "direct modeling"; everything physically represented

• Count all
• Taking away
• Trial and error (*)
• Matching (*)

Level 2 - "counting" strategies; only one number is physically represented

• Counting on
• Count down

Level 3 - "convert to an easier problem", then may use other levels or numbers

• Make a ten
• Doubles +/–n
• Rearrange (e.g., thinking of subtracting as finding an unknown addend)
• Commutative property

Model how to solve each CCSS problem type using strategies listed. Next class groups will present based on random assignments of types, unknowns, and strategies.

Result unknown Change unknown Start unknown
1. count all
2. counting on
3. (varies)
1. n/a
2. counting on
3. (varies)
1. trial and error
2. n/a
3. commutative prop.
Take from
1. taking away
2. counting on/down
3. rearrange
1. n/a
2. counting on/down
3. rearrange
1. trial and error
2. n/a
3. rearrange
Put together /
take apart
1. count all
2. counting on
3. (varies)
1. n/a
2. counting on
3. (varies)
1. n/a
2. n/a
3. n/a
Difference unknown Bigger unknown Smaller unknown
Compare
1. matching
2. counting on
3. (varies)
1. matching
2. counting on
3. (varies)
1. matching
2. counting down
3. (varies)

Make example problems for each of the Level 3 strategies.