Pear: 780*3/ 13= 180KG.

Apple: 780*4/ 13=240KG.

Grapefruit: 780*6/ 13=360KG.

Multiplying data fraction by integer has the same meaning as integer multiplication, and it is a simple operation to find the sum of several identical addends.

Fractions multiplied by integers have the same meaning as integer multiplication. Multiplying a number by a fraction can be regarded as finding a fraction of this number.

Fractional multiplication is a mathematical operation method. The numerator of the fraction is multiplied by the numerator and the denominator is multiplied by the denominator. What can be reduced must be reduced first, and whether the numerator can be multiplied by the denominator. When doing the first step, we should think about whether the numerator of one number and the denominator of another number can be reduced (except 0).