You have to use associative property to find 2*30
Two times 30 can be expressed as 30+30
[tex]2\cdot30=30+30=60[/tex]30 can be expressed as 2*15
So another way of solving this calculation is by doing
[tex]2(2\cdot15)=60[/tex]Or
[tex](2\cdot2)\cdot15=4\cdot15=60[/tex]