8. Teach Your Kid Number Conservation
At age 3 or 4, the length of something counts for more than the number of something. For instance, if your child sees a row of four cups spaced 3" apart and a second row of four cups spaced 1" apart, he may think that the first row has more cups. Show your child that both rows contain the same number of cups, even though the first row is longer. Conservation of number usually develops around age 5.