To find out what should be added to x to get the sum as 1.1 , we first need to calculate the value of x : x=1.011+10.11−12.101+0.1011 x=1.011+10.11−12.101+0.1011 x=(1.011+0.1011)+10.11−12.101 x=1.1121+10.11−12.101 x=11.2221−12.101 x=−0.8789 Now, to find what should be added to x to get the sum as 1.1 , we subtract x from 1.1: Addition needed =1.1−(−0.8789) Addition needed =1.1+0.8789 Addition needed =1.9789 So, 1.9789 should be added to x to get the sum as 1.1 .