Обчисли:
1) $\frac{5}{19}$ + $\frac{7}{19}$ – $\frac{4}{19}$;
2) 7 $\frac{5}{7}$ + $\frac{6}{7}$;
3) 1 – $\frac{9}{13}$;
4) 9 $\frac{7}{13}$ – 6 $\frac{9}{13}$.
Розв'язок:
1) $\frac{5}{19}$ + $\frac{7}{19}$ – $\frac{4}{19}$ = $\frac{12}{19}$ – $\frac{4}{19}$ = $\frac{8}{19}$;
2) 7 $\frac{5}{7}$ + $\frac{6}{7}$ = 7 $\frac{11}{7}$ = 8 $\frac{4}{7}$;
3) 1 – $\frac{9}{13}$ = $\frac{13}{13}$ – $\frac{9}{13}$ = $\frac{4}{13}$;
4) 9 $\frac{7}{13}$ – 6 $\frac{9}{13}$ = $\frac{124}{13}$ – $\frac{87}{13}$ = $\frac{37}{13}$ = 2 $\frac{11}{13}$.