Addition & Subtraction w/in 99 - 2nd Grade

By the end of 2nd grade students are expected to fluently add and subtract numbers within 99 using knowledge of place value. Below are videos that explain several strategies that, with a little bit of practice, lead to fluently and mentally being able to add and subtract 2-digit numbers. All of these strategies use an understanding of place value and the flexibility of numbers.

Using Place Value Blocks to Add.mp4

Adding Using Place Value Blocks

Using Place Value Blocks to Subtract.mp4

Subtracting Using Place Value Blocks

Partial Sums.mp4

Adding Using Partial Sums

Partial Differences.mp4

Subtracting Using Partial Differences

Open Number Line Addition.mp4

Adding Using an Open Number Line

Open Number Line Subtraction.mp4

Subtracting Using an Open Number Line

These ladies used different strategies to solve 34+26+18. They double checked their work with a calculator and were all smiles when the answers matched.

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