a)25.3+0.7-21.9830-[tex] \frac{16}{99} [/tex]=4
1)25.3+0.7=26
2)-[tex] 21\frac{83}{99} - \frac{16}{99} [/tex]=-[tex] \frac{2178}{99} [/tex]=-22
3)26-22=4
b)2.71-0.8(2)+1.2(5)+[tex] 1\frac{3}{5} [/tex]-0.65(4)=[tex] \frac{271}{100}- \frac{80}{90} + \frac{120}{90} + \frac{8}{5} - \frac{650}{900}= \frac{2439-800+1200+1120-650}{900} = \frac{3309}{900} =3 \frac{609}{900} [/tex]
