To find standard form, simplify the number as much as possible:
6,000,000,000+300,000,000+40,000,000+2,000,000
6,000,000,000+300,000,000 = 6,300,000,000
6,300,000,000 + 40,000,000 = 6,340,000,000
6,340,000,000 + 2,000,000 = 6,342,000,000
6,342,000,000 is your answer
hope this helps