Students order small numbers written in standard form, and explain why they are ordered in that way. The numbers are the lengths of some microscopic animals.
Students write down an explanation of how the front-end estimation strategy works in addition problems to give information on their understanding of the strategy.
Students discuss making an interval estimate in multiplication problems (i.e., getting a lower and an upper limit for the actual answer using the front-end and rounding-up estimation methods). They then use this method on two problems.