a/ 27.121- 87.27 + 73.34
= `27. ( 121 - 87 ) + 73.34`
= `27. 34 + 73. 34`
= `34. ( 27 + 73 )`
= `34. 100`
= `3400`
b/ `10^2 - [60:(5^6:5 ^4- 3.5)]`
= `10^2 - [60:(5^2- 15)]`
= `10^2 - [60:(25- 15)]`
= `10^2 - [60: 10]`
= `10^2 - 6`
= `100 - 6`
= `94`
c/ `500- {5.[409—(2^3``.3—21)]}+103.115`
= `500- {5.[409—(8.3—21)]+103.115`
= `500- {5.[409—( 24—21)]}+103.115`
= `500- {5.[409—3]}+103.115`
= `500- {5.406}+103.115`
= `500- 2030 + 103.115`
= `(- 1530) + 11845`
= `10315`
