Most calculators used directly can’t provide 100% accuracy.
(568000+792)(843000+615)=
478824000000+349320000+667656000+487080=
478824487080+
1016976000
479841463080
Finally, use the calculator to do a direct calculation: 4.798414631×10¹¹.
The calculator rounded the last figure, but we can see what it should have been to 100% accuracy.
The calculator confirms our split calculation.