5/11×4/15=
9/14×5/12=
18×2/9=
15×9/10=
3/7×21=
4/9×6=
15×2ц3/5=
1ц3/7×2ц4/5=

5/11×4/15 = (5×4)/(11×15) = 4/(11×3) = 4/339/14×5/12 = (9×5)/(14×12) = (3×5)/(14×4) = 15/5618×2/9 = (18×2)/9 = 2×2 = 415×9/10 = (15×9)/10 = (3×9)/2 = 27/23/7 × 21 = (3×21)/7 = 3×3 = 94/9×6 = (4×6)/9 = 4×2 = 8Хз что за «ц»