1, in preschool mathematics, according to the characteristics of the topic itself, we can simplify the complex, change the difficult to the easy, and calculate quickly and accurately.

2. Calculation method of "rounding". Calculation: 24+44+56. Solution: (1) 24+44+56 = 24+(44+56) = 24+100 =124. Because 44+56= 100 is an integer, let's calculate their sum first.