= 1/4+ 1/2

=3/4 (cup),

( 1- 1/2)× 1/2

= 1/2× 1/2× 1/2

= 1/4 (cup),

Lele drank 3/4 cups of pure milk and 1/4 cups of water.

Extended data:

Cultivate the ability to solve such problems;

Master the laws of multiplication and exchange;

Throughout the different teaching materials such as People's Education Edition and Soviet Education Edition, the education of children's multiplication and division method has been ignored. As shown in the figure below, although children can know 2× 5 = 10 and 5× 2 = 10, few children know why this happens, and it is difficult to use the exchange law flexibly to solve their own problems.