When asked how much time elapsed between 8:30 and 11:00, many students reply "3 hours 30 minutes, because from 8:00 to 11:00 is 3 hours, plus 30 more minutes." This demonstrates children's inability to think hierarchically about higher- and lower-order units. The speaker will discuss the problem with respect to time, place value, and fractions.

Presentation Format: 3-5 Session
Grade Band Audience: PreK to 2, 3 to 5