Curriculum placement

Grade 2. This describes the skill, not a learner estimate.

Explaining why a strategy works

Explain why addition and subtraction strategies work using place value and properties of operations

Problem types

  • Why does this step work?
  • Find the step that went wrong
  • What does the carry or borrow mean?
  • Why line up the digits?

Builds on

Leads to

  • Adding and subtracting within 1,000 ยท Extend the idea

    A strategy works because breaking a number by place, and trading 10 ones for 1 ten, keep the amount the same. The same reasons make quick addition and subtraction within 1000 work.

Related skills

None listed.

Open the interactive map to explore lessons and skill connections.