Question

Dau coroană şi 25 de puncte

Answer 1

Mod de lucru:
se introduc intregii in fractie, se aduce la acelasi numitor comun, se efectueaza calculele apoi rezultatul fiind fractie supraunitara, se scot intregii din fractie.

$a) 5 \frac{2}{5}+3\frac{3}{10}= \frac{5\cdot5+2}{5} +\frac{3\cdot10+3}{10} = \frac{27}{5} +\frac{33}{10} = \frac{54+33}{10}= \frac{87}{10}=8 \frac{7}{10} \\ \\ 2 \frac{3}{4}+3\frac{7}{8}= \frac{2\cdot4+3}{4} +\frac{3\cdot8+7}{8} = \frac{11}{4} +\frac{31}{8} = \frac{22+31}{8}= \frac{53}{8}=6 \frac{5}{8}$

b) se procedeaza aproape identic doar ca este vorba de operatia de scadere

$7\frac{2}{3}+3\frac{5}{9}= \frac{7\cdot3+2}{3} +\frac{3\cdot9+5}{9} = \frac{23}{3} +\frac{32}{9} = \frac{23\cdot3+32}{9}= \frac{69+32}{9}= \frac{101}{9}=11 \frac{2}{9}$

$11\frac{1}{2}+5\frac{3}{8}= \frac{11\cdot2+1}{2} +\frac{5\cdot8+3}{8} = \frac{23}{2} +\frac{43}{8} = \frac{23\cdot4+43}{8}= \frac{92+43}{8}= \frac{135}{8}=16 \frac{7}{8}$