Look closely to see if you can find D.C.'s error in his addition.

Warm up with a Mystery Math Mistake to tell whether Dotson's 10-frames represent a number more than his focus number. Examine a train to find shapes. Put together shapes to make familiar objects.

Warm up with a Mystery Math Mistake to add 9 and 5 using a double 10-frame and a decompose strategy. Use near-doubles to add with double 10-frames and a compensation strategy.