**unit 2: patterns in addition and subtraction**

**LG:**We are learning how to add and subtraction 2-digit and 3-digit numbers.

**SC:**We know that when adding we can carry over to the next place value and with subtraction, we can borrow 10 from the number to the left.

**LG:**We are learning to use mental math to add and subtract.

**SC:**We know that when adding, add on tens, and then add on ones. We can also take one to give to the other.

We can take away tens, and then take away ones. We can add to match the ones, and then subtract. We can add to make a friendly number.

**LG:**We are learning to estimate sums and differences.

**SC:**We know that we can estimate when we do not need to know the exact answer.

**LG:**We are learning to use standard algorithm for addition and subtraction.

**SC:**We know that we can use the standard algorithm or other strategies to find the sum or difference.