6.785+0.9868

6.785+0.9868
= 6.785+(1-0.0132)
= 6.785+1-0.0132
= 7.7850-0.0132
= 7.7618

2009-11-13 22:46:16 補充：
Sorry, 7.7850-0.0132=7.7718!

Not sure what you're trying to ask here.

But if you want to ask/write the question in English, it would be the following:

Six point seven eight five plus zero point nine eight six eight.

6.785+0.9868
=7.7718
or =7.772 (cor. to 4 sig. fig.)
or =7.77 (cor. to 3 sig. fig.)
or =7.8 (cor. to 2 sig. fig.)
or =8 (cor. to integer)