find each product mentally using the distributive property

i know for 4 (10.2) i do this
= 4 (10 + 2)
= 4 (10) + 4 (2)
= 40. + .8
= 40.8
but I am not sure how to show work on on following 2 problems:
11.6 (9)

and 3.4 (5)

1 answer

Three ways you could do the multiplication mentally:

9(11.6)=9*10 + 9*1.6 = 90 + 14.4 = 104.4

9(11.6)=9*11 + 9*0.6 = 99 + 5.4 = 104.4

11.6(9)= 11.6*(10-1) =116 - 11.6 = 104.4