4 целых 3/10-1 целая 11/15
4ц3/10-1ц11/15=3ц(9-22/30)=2ц(30+9-22)/30=2ц17/30
4 3/10-1 11/15= 43×3/10-26×2/15=129-52/30=77/30= 2 17/30