What is the distributive property of multiplication over subtraction using 65x39?

Answer 1

65*39 = 65*(40-1) = 65*40 - 65*1 = 2600 - 65 = 2535

To calculate 65*40 in your head, you can try

6.5 is half of 13 ie 6.5*2 = 13

so 65*2 = 130

so 65*4 = 260

and so 65*40 = 2600