Learn Zillion

 
Find the difference in the length of two objects using addition        LZ2387
 
 
Use everyday objects to determine the difference in the length of two objects    LZ2536

http://learnzillion.com/lessons/2536-use-everyday-objects-to-determine-the-difference-in-the-length-of-two-objects

 Add within 20 by regrouping on a ten frame    LZ2686

http://learnzillion.com/lessons/2686-add-within-20-by-regrouping-on-a-ten-frame

 Combine tens, ones, and hundreds to create numbers    LZ3384

http://learnzillion.com/lessons/3384-combine-tens-ones-and-hundreds-to-create-numbers