К) 2/3 : 18; л) 8/27 • 36; м)10:4/15
2/3 : 18 = 2/3 * 1/18 = 1/3 * 1/9 = 1/27 8/27 * 36 = 8/3 * 4 = 32/3 = 10 2/3 10 : 4/15 = 10 * 15/10 = 15