The children have been learning about Measurement in Math. They've used inches and centimeters rulers to explore length. I have found these websites that give extra support in measuring.
MATH:
http://www.funbrain.com/cgi-bin/meas.cgi?A1=s&A2=0&A3=0
http://www.funbrain.com/cgi-bin/meas.cgi?A1=s&A2=1&A3=0
http://www.pbs.org/parents/earlymath/grades_games_timetomove.html