(1) 2 3 +( 2 3 - 1 4 )= 2 3 + 5 12 = 13 12 ;答:两数之和是 13 12 .(2) 3 5 -( 1 10 + 3 8 )= 3 5 - 19 40 = 1 8 ;答:差是 1 8 .(3) 3 8 -( 2 3 - 1 2 )= 3 8 - 1 6 = 5 24 ;答:少 5 24 .