6.87 × 107 written in regular notation is 68,700,000
687 = (6 x 100) + (8 x 10) + (7 x 1)
125,000,000
5.20 x 10-7 = 0.00000052
10 to the seventh power - or 10,000,000. When multiplying numbers with exponents - you add the exponents together.
4.2 x 107 = 42000000
80^7 = 2097152 X 10^7
27.86 x 107 = 270,860,000
24 X 107 = 240,000,000 ================two hundred and forty million
687 * 345 = 237,015..........687.......x 345=======........3435.......... (687 x5)......2748............ (687 x 4).....2061............. (687 x 3)=======.....237015.......... (3435 + 27480 + 206100)
The answer is 687 x 10-3
2.67 x 10 to the seventh power. Hard to write here, but 10 with a little seven superscript.
687 x 60 = 41220