Răspuns :
Răspuns:
Explicație pas cu pas:
a)
[tex]\frac{31}{10}+\frac{28}{9}=\frac{31*9+28*10}{90}=\frac{279+280}{90}=\frac{559}{90}=6,2(1)[/tex]
b)
[tex]\frac{2}{100}+\frac{2}{99}=\frac{2*99+2*100}{9900}=\frac{198+200}{9900}=\frac{398}{9900}=0,04(02)[/tex]
c)
[tex]\frac{21}{9}+\frac{11}{9}=\frac{32}{9}=3,(5)[/tex]
d) - lipseste o paranteza la 0,41) , asa ca facem mai intai cu 0,4(1) apoi cu 0,(41)
[tex]0,(14)+0,4(1)=\frac{14}{99}+\frac{37}{90}=\frac{14*90+37*99}{8910}=\frac{1260+3663}{8910}=\frac{4923}{8910}=0,5(52)[/tex]
si
[tex]0,(14)+0,(41)=\frac{14}{99}+\frac{41}{99}=\frac{55}{99}=0,(5)[/tex]
e)
[tex]\frac{1}{9}+\frac{12}{99}+\frac{123}{999}=\frac{1}{9}*(1+\frac{12}{11}+\frac{123}{111})=\frac{1}{9}*\frac{11*111+12*111+123*11}{11*111}=\frac{1221+1332+1353}{10989}=\\\\=\frac{3906}{10989}=0,(355446)[/tex]
f)
[tex]\frac{191}{90}-\frac{109}{90}=\frac{191-109}{90}=\frac{82}{90}=0,9(1)[/tex]
g)
[tex]\frac{181}{90}+\frac{19911}{9900}-\frac{12090}{9990}=[/tex]
[tex]=\frac{1}{90}(181+\frac{19911}{110}-\frac{12090}{111})=[/tex]
[tex]=\frac{1}{90}*\frac{181*110*111+19911*111-12090*110}{110*111}=[/tex]
[tex]=\frac{2210010+2210121-1329900}{90*110*111}=[/tex]
[tex]=\frac{3090231}{1098900}= 2,812(113022)[/tex]
h)
[tex]\frac{181}{90}+\frac{19911}{9900}+\frac{12090}{9990}=[/tex]
[tex]=\frac{1}{90}(181+\frac{19911}{110}+\frac{12090}{111})=[/tex]
[tex]=\frac{1}{90}*\frac{181*110*111+19911*111+12090*110}{110*111}=[/tex]
[tex]=\frac{2210010+2210121+1329900}{90*110*111}=[/tex]
[tex]=\frac{5750031}{1098900}= 5,232(533442)[/tex]