( 2 целых 6/7-1 целая 1/2) * 5 целых 1/4

[latex](2\frac{6}{7}-1\frac{1}{2})*5\frac{1}{4}=(2\frac{12}{14}-1\frac{7}{14})*\frac{21}{4}= 1\frac{5}{14}*\frac{21}{4}=\frac{19*21}{14*4}=7\frac{1}{8}[/latex]