によって Melody Wolen 11年前.
389
もっと見る
a+0=a
(8+7)+3=8+(7+3)
8+7=7+8
to conceptualize a number as being made up of 2 or more parts is the MOST important relationship to develop
10 is an essential numbers, must know how any given number relates to ten
knowing which numbers are one more or two less than any given number
5:15-3:45=1:30 (base is 60, have to carry enough over from other place values to have enough minutes)