Help your kiddos master three-digit addition using this "Add Across, Then Down" Expanded Form strategy for adding based on place value. Supports Common Core standards 2.NBT.5 and 3.NBT.2, addition within 1000 based on place value strategies.
This strategy requires students to first expand the numbers in a 3-digit addition problem into place value charts, then asks them to add across the rows of the charts to arrive at the total number of hundreds, tens, and ones in the equation. Students then