1) 1/9×1ц5/6+1ц1/6×1/9= 1/9×11/6+7/6×1/9= 11/54+7/54= 18/54= 1/3
2) 1ц3/8×3/5-3/5×1/8= 11/8×3/5-3/40= 33/40-3/40= 30/40= 3/4
3) 2ц1/3+4ц1/10÷(2ц7/15-5/12)×5/6= 7/3+41/10÷(37/15-5/12)×5/6= 7/3+41/10÷((148-25)/60)×5/6= 7/3+(41/10÷123/60)×5/6= 7/3+(41/10×60/123)×5/6= 7/3+2×5/6= 7/3+5/3= 12/3 = 4
4) 4ц5/12-1ц1/2÷(2ц1/6+8/15)×1ц4/5= 53/12-3/2÷(13/6+8/15)×9/5= 53/12-3/2÷((65+16)/30)×9/5= 53/12-(3/2÷81/30)×9/5= 53/12-(3/2×30/81)×9/5= 53/12-45/81×9/5= 53/12-1= 4ц5/12-1= 3ц5/12