2^{nd} part: 113. + (-111. + 7.51)
(-111. + 7.51) = - .111 x 10^{3 }+ .751 x 10
= 10( - .111 x 10^{2} + .751)
= 10(-11.1 + .751)
= 10(- 10.349)
= - 103.49
now, 113. + (- 103.49) = .113 x 10^{3} - .10349 x 10^{3}
= 10^{3}(.113 - .103) // ignor 49 bcz three-digit floating point arithmetic with rounding
= 10^{3} x .010
= 10