Are different bars defined by the explanatory variable or by the purpose variable? is each bar segmented according to the explanatory variable or the response variable?

,.

(1,4) is on graph of f(x)

f(1) = 4

so 1/4 f(x)

1/4 f(1)

1/4. ×4

1

so point for function 1/4. f(x) is (1,1)

so, converting firstly the mixed fractions to improper fractions and then "adding".