11/18+1/12=(11*2)/(18*2) + (1*3)/(12*3)=22/36 + 3/36 = 25/36
7/8 - 3/14 = 49/56 + 12/56 = 61/56= 1 5/56
9/16 + (0,25 - 5/24) = 9/16 + ((25*6)/600-(5*25)/600)=9/16 + (150/600 - 125/600) = 9/16 + 25/600 = 9/16 + 1/24 = 27/48 + 2/48 = 29/48
1) 1 5/9 : 7/24 = 14/9 * 24/7 = 16/3=5 1/3
2) 7 - 5 1/3 = 1 2/3
3) 1 2/3 : 20/27 = 5/3 * 27/20 = 9/4 = 2 1/4
ответ: 2 1/4
<span>1) 297мин+137мин-209мин=225мин=3ч, 45мин
</span>2) 1089c-466c+2915c=3538c=58мин, 58с
3) 7300г-940г=6360г=6кг, 360г
4) 24000м-8950м=15015м=15 км,15м