`a)3^6:3^2-3^4`
`=3^(6-2)-3^4`
`=3^4-3^4`
`=0`
`b)5^3:5^3+1`
`=1+1`
`=2`
`c)(125:25)^3`
`=(5^3:5^2)^3`
`=(5^(3-2))^3`
`=5^3`
`=125`
`d)``[(6^2:2^2-7^3:7^2)+13]:3`
`=[(6:2)^2-7^(3-2)+13]:3`
`=[3^2-7+13]:3`
`=[2+13]:3`
`=15:3`
`=5`
`e)2^5. 5^2. 3-81:3^2`
`=32.25.3-3^4:3^2`
`=32.25.3-3^(4-2)`
`=800.3-3^2`
`=3.(800-3)`
`=3.797`
`=2391`
`f)3^2.(7-6)^10-(2^4+3^2):5^2`
`=3^2. 1-(16+9):5^2`
`=9-25:5^2`
`=9-5^2:5^2`
`=9-1`
`=8`
