a) 2⁰+2⁻²:(⅔)⁻²-5×(-2)⁻²+(½)⁻²+¾

2⁰+2⁻²:(⅔)⁻²-5×(-2)⁻²+(½)⁻²+¾=1+(½)²:(3/2)²-5×(-1/2)²+2²+¾= =1+¼:9/4-5/1×1/4+4+3/4= 1¼:9/4-5/4+4+¾= 5/4:9/4-5/4+4+3/4= =5/4×4/9-5/4+4+3/4=20/36-5/4+4¾=20/36-5/4+19/4=20/36+14/4= =20/36+126/36=146/36=4 2/36=4 1/18