a. 27.75+25.27-150=27.(75+25)-150
= 27.100-150
= 2700-150
= 2550
b.142-[50-(23.10-23.5)]=142-[50-23(10-5)]
= 142-[50-23.5]
= 142-[50-115]
= 142-(-65)
= 207
c. 375:{32-[4+(5.32-42)]}-14=375:{32-[4+(160-42)]}-14
= 375:[32-[4+118]}-14
= 375:{32-122}-14
=375:(-90)-14
=$\frac{-25}{6}$ -14
=$\frac{-109}{6}$
d. {210:[16+3(6+3.22)]}-3={210:[16+3(6+66)]}-3
= {210:[16+3.72]}-3
= {210:[16+216]}-3
={210:232}-3
= $\frac{105}{116}$-3
= $\frac{-243}{116}$
e. 500-{5[409-(2³.3-21)²]-1724}=500-{5[409-(24-21)²]-1724}
= 500-{5[409-3²]-1724}
= 500-{5.400-1724}
= 500-{2000-1724}
= 500-276
= 224
