Excel 2010 Sumif formula (IF Sum equals amount out ok)

[Smudge80]

Hello Everyone!

really hope can assist on this.

Have 2 large data sets across 2 worksheets. Want to lookup a quantity on 1 sheet that if equals same amount put ok in required cell . If not leave blank.
so if a1 on sheet 1 is 100 and a1 on sheet 2 is 100 put ok. it would have to look up the supplier name against quantity first.

Thanks!