a) `37 . 143 + 57 . 37 + 1300`
`= 37. (143 + 57) + 1300`
`= 37. 200 + 1300`
`= 7400 + 1300`
`= 8700`
c) `2. {80 - [3. (12 + 3. 5) + 19] : 20}`
`= 2. {80 - [3. (12 + 15) + 19] : 20}`
`= 2. {80 - [3. 27 + 19] : 20}`
`= 2. {80 - [81+ 19] : 20}`
`= 2. {80 - 100 : 20}`
`= 2. {80 - 5}`
`= 2. 75`
`= 150`