This task can be used as an introduction to the standard algorithm for multiplying decimals. It is designed to be used with the Decide and Defend instructional routine developed by Amy Lucenta, Grace Kelemanik, and Susan Janssen Creighton in their book Routines for Reasoning. Decide and Defend is an instructional routine in which students make sense of another's line of mathematical reasoning, decide if they agree with that reasoning, then draft an argument defending their decision. More info