\({5 \over 2a}+{8 \over 2a}={13 \over 2a}\)

\({7 \over a}-{4 \over 3a}={21 \over 3a}-{4 \over 3a}={17 \over 3a}\)

\({7 \over 2p}-{5 \over 3q}={21q \over 6pq}-{10p \over 6pq}={21q-10p \over 6pq}\)

\(4-{5 \over 6x}={4 \over 1}-{5 \over 6x}={24x \over 6x}-{5 \over 6x}={24x-5 \over 6x}\)

\({8x \over y}-{7 \over 2y}={16x \over 2y}-{7 \over 2y}={16x-7 \over 2y}\)

\({7a \over a}={7 \over 1}=7\)

\({x \over 2x}={1 \over 2}\)

\({8p \over -20p}=-\frac{2}{5}\)

\({-6a \over 3a}=-2\)

\({12xy \over -27xz}=-{4y \over 9z}\)

\({6b \over -21ab}=-{2 \over 7a}\)

\({16xyz \over -2yz}=-8x\)

\({5xy \over y}+{7xz \over z}=5x+7x=12x\)

\(4x-{2 \over 9x}={4x \over 1}⋅{9x \over 9x}-{2 \over 9x}={36x^2 \over 9x}-{2 \over 9x}={36x^2-2 \over 9x}\)

\({5q \over 6p}-{7p \over 4q}={10q^2 \over 12pq}-{21p^2 \over 12pq}={-21p^2+10q^2 \over 12pq}\)

\({7 \over x}⋅{5 \over y}={35 \over xy}\)

\({a \over 5}⋅{4 \over b}={4a \over 5b}\)

\(-{6 \over 7}⋅a=-{6a \over 7}\)

\({9q \over p}⋅{p+8 \over 5}={9q(p+8) \over 5p}={9pq+72q \over 5p}\)

\({6 \over x}:{5 \over y}={6 \over x}⋅{y \over 5}={6y \over 5x}\)

\(-{4 \over 9}:a=-{4 \over 9}:{a \over 1}=-{4 \over 9}⋅{1 \over a}=-{4 \over 9a}\)

\(-{9 \over 2}:{x+5y \over y}=-{9 \over 2}⋅{y \over x+5y}=-{9y \over 2(x+5y)}=-{9y \over 2x+10y}\)

\({8a \over 7}+{a-9 \over 6}={48a \over 42}+{7(a-9) \over 42}={48a+7(a-9) \over 42}={55a-63 \over 42}\)