`a,7.` $5^{2}$ `-24` : $2^{2}$
`=7.25-24:4`
`=175-6`
`=169`
`b,` $5^{3}$ . `20` `-` $5^{3}$ . `17`
`=` $5^{3}$ . `(20-17)`
`=` $5^{3}$ . `3`
`=` `125.3
`=375`
`c,47.313+87.47`
`=47.(313+87)`
`=47.400`
`=18800`
`d,200:[117-(23-6)]`
`=200:[117-17]`
`=200:100`
`=2`
`e,` $7^{7}$ : $7^{5}$ `+` $2^{2}$ . $2^{3}$
`=` $7^{2}$ `+` $2^{5}$
`=` `49+32`
`=81`
`f,(48.52-46.52):52`
`=[52.(48-46)]:52`
`=[52.2]:52`
`=104:52`
`=2`