Question

can use only 5 odd numbers from 1 to 15 to get 30 by addition only. Solve it

Answer 1

By using the factorial sign ! 

3 + 5 + 7 + 9 + 3! = 30

3! means that = 1*2*3
                      = 6

So we concluded that 

3 + 5 + 7 + 9 + 6 = 30

Answer 2

3!+3!+3!+3!+3!=30

Note that 3!=3*2*1=6