<span>2,5(0,3r +2k)-(k+0,1r) = 0,75r + 5k - k - 0,1r = 0,65r + 4k</span>
8 9/8 + 2 18/11 - 3 1/4 = 73/8 + 40/11 - 13/4 =(73 × 11 + 40 × 8 - 13 × 22)/88 = 803/88 + 320/88 - 286/88 = 837/88 = 9 45/88
6020:70=86
750:50-40:5=7
1)750:50=15
2)40:5=8
3)15-8=7
360:6-20:1=40
1)360:6=60
2)20:1=20
3)60-20=40