1)<span>1/12+3 4/15</span>=3+<span>1/12</span>+<span>4/15</span> = 3+<span>1·5/12·5</span>+<span>4·4/15·4</span>=3+<span>5/60</span>+<span>16/60</span>=3+ <span>5+1660</span>=3 <span>21/60</span>=3 <span>7·3/20·3</span>=3 <span>7/20</span> = 3.35
2)3 19/21+2 2/3=5+<span>19/21</span>+<span>2/3</span>=5+<span>19·1/21·1</span>+<span>2·7/3·7</span>=5+1<span>9/21</span>+<span>14/21</span>=5+ <span>19+14/21</span>=5 <span>33/21</span>=5 11·3/7·3=5 <span>11/7</span>=5 <span>4+1·7/7</span>=6 <span>4/7
</span>3)5*5 4/5=5·4+5·5/5=5<span>·</span><span>29/5</span> = <span>5·29/5</span> = <span>145/5</span> = <span>29·5/5</span><span> = 29
</span>И все в таком роде
4)<span>1 7/9*1 2/3=2 26/27
</span>5)<span>5 1/10-1 1/16=4 3/80
</span>6)<span>4-2/7=3 5/7
</span>7)<span>4/9+1 2/3=2 1/9
</span>8)5 3/8-2 11/16=2 11/16
Решение смотри на фотографии
(3,2 + 0,32 : 0,1 - (50 - 7,2) * 0,1) * 100 = -428
1) 50 - 7,2 = 42,8
2) 0,32 : 0,1 = 3,2
3) 42,8 * 0,1 = 4,28
4)3,2 - 3,2 = 0
5) 0 - 4,28 = - 4,28
6) -4,28 * 100= -428
Решение
z = 66 = 3*2*11
z = 72 = 2*2*2*3*3
100кг =2/5
1/5=50 в магазине 5/5 =250
делим 250:10=25
складываем 100+25=125
надеюсь правильно