Be careful, at least one out of the next two means either one or BOTH will have blue eyes i.e. the 25% refers to the probability of one child having blue eyes. In these sort of Qs, to save time, just calculate the probability of the opposite not happening. Since 1/4 will have blue eyes, then 3/4 will have brown ones.

Both children having brown eyes (zero blue) is 3/4 x 3/4

So the opposite would be 1 - (3/4 x 3/4) which equals to about 44%

To simplify your life, when you see AT LEAST always calculate the probability of obtaining the complement then deduct it from 1

EDIT: To clarify about the other (harder way), you'd add the probability of only the 1st kid being blue, only the 2nd being blue, and both being blue:

0.25x0.75 + 0.75x0.25 + 0.25x0.25 = 0.4375 = 0.44