(9-2 1/2×2 1/7)×21/46
(9-2 1/2×2 1/7)×21/46=1 1/2 1)2 1/2*2 1/7=5/2*15/7=5 5/7 2)9-5 5/7=8 7/7-5 5/7=3 2/7 3)3 2/7*21/46=23/7*21/46=3/2=1 1/2