47 * 19 - 2400 : 80 = 893 - 30 = 863
(62 + 38) - (142 - 42 ) = 100 - 100 = 0
(8412 : 4 ) * (75 * 50) = 2103 * 3750 = 7886250
(48 + 52 ) : (50 : 5 ) = 100 : 10 = 10
( 71 * 63 ) * ( 17 * 3 ) = 4473 * 51 = 228123
( 53 * 7 ) * ( 815 -793 ) = 371 * 22 = 8162