2.NBT.7 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.

Open Number Line Addition Start at 459 and jump up to 113 100 10 3 459 559 569 572

Open Number Line Addition 567 + 233 What will the ones value be? 100 100 10 10 10 3 567 667 767 777 787 797 800

Open Number Line Addition Use an Open Number Line to add. Be prepared to present your Open Number line

Open Number Line Subtraction 546 – 399 Start at the smaller number and hop up. 1 100 10 10 10 10 6 399 400 500 510 520 530 540 546 Let students see that this is like addition. Is this the only way to hop up? Is there a way I can hop up with less hops?

Open Number Line Subtraction 600 – 254 You try and be prepared to explain your Open Number Line

Open Number Line I have a collection of 234 rocks. I found 142 more rocks at the river. How many rocks do I have now? Collect student answers and put all the answers on the board. Then weed out any answers that the class thinks is incorrect. Have students present their strategy on a white board or in front of the class. Show the different ways students thought about their hops.

Open Number Line I have a bag of 345 Marbles. I gave 68 to my friend. How many marbles do I have left?

Base Ten Blocks for addition and subtraction

Addition using Base Ten Have students come to the board and circle any tens that can be traded for a hundred. Have student come to the board and circle any ones that can be traded for a ten. Tell the solution

Subtraction using Base Ten Take away any hundreds and then tens and then ones