428. Есептеңдер: 1) 25/28 − 2/21; 2) 41/54 − 35/72; 3) 20/21 − 3/14; 4) 40/143 + 39/110; 5) 43/140 + 41/150; 6) 73/80 − 31/100.

Әр өрнекте бөлшектерді ортақ бөлімге келтіріп есептейміз.

1. \(\frac{25}{28}-\frac{2}{21}=\frac{75}{84}-\frac{8}{84}=\frac{67}{84}\).
2. \(\frac{41}{54}-\frac{35}{72}=\frac{164}{216}-\frac{105}{216}=\frac{59}{216}\).
3. \(\frac{20}{21}-\frac{3}{14}=\frac{40}{42}-\frac{9}{42}=\frac{31}{42}\).
4. \(\frac{40}{143}+\frac{39}{110}=\frac{400}{1430}+\frac{507}{1430}=\frac{907}{1430}\).
5. \(\frac{43}{140}+\frac{41}{150}=\frac{645}{2100}+\frac{574}{2100}=\frac{1219}{2100}\).
6. \(\frac{73}{80}-\frac{31}{100}=\frac{365}{400}-\frac{124}{400}=\frac{241}{400}\).

Жауабы: 1) 67/84; 2) 59/216; 3) 31/42; 4) 907/1430; 5) 1219/2100; 6) 241/400.