I used this independent work while teaching to the common core standard 2.NBT.B.7.
The worksheet shows an example for the students to look back at for help, three number line addition problems, a problem for students to solve using an strategy they know, and a spot that requires them to explain their thinking to the problem.
I used the LearnZillion website to preteach the lesson on using a numberline to add two three digit numbers. Below is the link. Scroll down to Section 5 and click lesson set 3.
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