a)
3 1/4 - 1 1/2 + 2 7/8 =
3\frac{1}{4}-1\frac{1}{2}+2\frac{7}{8}=\frac{13}{4}-\frac{3}{2}+\frac{23}{8}=\frac{26}{8}-\frac{12}{8}+\frac{23}{8}=\frac{14+23}{8}=\frac{37}{8}=4\frac{5}{8}
21 * 1 \frac{1}{14} =21*\frac{15}{14}=\frac{3*15}{2}=\frac{45}{2}=22\frac{1}{2}
1 2/5 * 3 13 = zapis ??
b)
(\frac{3}{4})^2 =\frac{3^2}{4^2}=\frac{9}{16}
(1 \frac{1}{2})^3 =\frac{3^3}{2^3}=(\frac{3}{2})^3=\frac{3*3*3}{2*2*2}=\frac{27}{8}
\frac{5}{6}:\frac{2}{9}=\frac{5}{6}*\frac{9}{2}=\frac{5}{2}=2\frac{1}{2}
c)
6:2\frac{1}{4}=6:\frac{9}{4}=6*\frac{4}{9}=2*\frac{2}{3}=\frac{4}{3}=1\frac{1}{3}
3\frac{3}{10}:11=\frac{33}{10}*\frac{1}{11}=\frac{3}{10}
3\frac{1}{3}:4\frac{1}{3}=\frac{10}{3}:\frac{13}{3}=\frac{10}{3}*\frac{3}{13}=\frac{10}{13}