№3: 2) 1/(1/36 − 1/44); 4) 1/(1/35 − 1/60); 6) 1/(1/72 − 1/99).

1. \(\frac{1}{\frac1{36}-\frac1{44}}=\frac{1}{\frac{44-36}{1584}}=\frac{1}{\frac1{198}}=198\).
2. \(\frac{1}{\frac1{35}-\frac1{60}}=\frac{1}{\frac{60-35}{2100}}=\frac{1}{\frac1{84}}=84\).
3. \(\frac{1}{\frac1{72}-\frac1{99}}=\frac{1}{\frac{99-72}{7128}}=\frac{1}{\frac3{792}}=264\).

Ответ: 2) 198; 4) 84; 6) 264.