A. 98 +47= 98+2+45
= 100+45=145
b 199+56= 199+1+55
= 200+55
= 255
c 2997 +113= 2997 + 3 +110
= 3000 +110
= 3110
a, 98+47=145
b,199+56=255
c,2997+113=3110
98 + 47 = 145
199 + 56 = 225
2997 + 113 = 3110
a) 98 + 47 = ( 98 - 3 ) + ( 47 + 3 ) = 95 + 50 = 145
b) 199 + 56 = ( 199 - 4 ) + ( 56 + 4 ) = 195 + 60 = 255
c) 2997 + 113 = ( 2997 - 7 ) + ( 113 + 7 ) = 2990 + 120 = 3110