Use place value understanding and properties of operations to add and subtract.
Add and subtract within 1000, using concrete models or drawings and strategies based on place value,
properties of operations, and/or the relationship between addition and subtraction; relate the strategy
to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts
hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.
• Students should be able to add within 100 (1nbt4).
• This will be the first formal experience students have subtracting within 1,000. Previously only addition within 100 was completed.