а).(6/14 +17/14)×7=6/2 +17/2=23/2=11 1/2 =11,5
б).(2/9 +(5×3)/(3×3))×3=(2/9 +15/9)×3=17/9 ×3=17/3=5 2/3
в).7/15(2 3/7 +7 4/7)=7/15 ×9 7/7=7/15 ×10=7/3 ×2=14/3=4 2/3
г).5/12(2 3/7 +3 4/7)=5/12 ×5 7/7=5/12 ×6=5/2=2 1/2=2,5
а).(6/14 +17/14)×7=6/2 +17/2=23/2=11 1/2 =11,5
б).(2/9 +(5×3)/(3×3))×3=(2/9 +15/9)×3=17/9 ×3=17/3=5 2/3
в).7/15(2 3/7 +7 4/7)=7/15 ×9 7/7=7/15 ×10=7/3 ×2=14/3=4 2/3
г).5/12(2 3/7 +3 4/7)=5/12 ×5 7/7=5/12 ×6=5/2=2 1/2=2,5