(1)5×998+10 = 5x (1000 -2 ) +10= 5000 -10 +10=5000(2)16.8×7/32+7.6×7/16= 16.8 x 7/32+(7.6x2)×7/32 = ( 16.8 + 15.2 ) x 7/32 = 3 2 x 7/32 = 7