`a ) 117 . ( 36 + 62 ) - 17 . ( 62 + 36 )`
`= 117 . 98 - 17 . 98`
`= 98 . ( 117 - 17 )`
`= 98 . 100`
`= 9800`
`b ) 1/7 : 5/17 + 1/7 : 5/18`
`= 1/7 : ( 5/17 + 5/18 )`
`= 1/7 : 175/306`
`= 306/1225`
`c ) 4 5/6 + 1/6 . ( 12 - 5 1/3 )`
`= 29/6 + 1/6 . ( 12 - 16/3 )`
`= 5 . 20/3`
`= 100/3`
`d ) {(9,45 - 3,2) × 4 : 0,2}/{(0,297 + 0,721) × 625}`
`= {6,25 × 4 × 5}/{1,018 × 625}`
`= {6,25 × 20}/{101,8 × 6,25}`
`= 20/{101,8} = 100/509`
`#dtkc`
