Most calculators can't handle that many digits, but you can type this sort of calculation in the Wolfram Alpha site.Note that for most practical applications, you don't need that many significant digits; so the number of digits handled by a scientific calculator (usually 10-12 digits) works quite well.
5 x 5 x 5 x 5 x 5 x 5 x 5 x 5 = 78,125
5 to the tenth power would be 5 X 5 X 5 X 5 X 5 X 5 X 5 X 5 X 5 X 5, or 9,765,625.
30
5 x 5 x 5 x 5 x 5 = 3,125
5x5x5x5x5x5=15,625.
(x-5) is the same as x-5
The twelve is an exponent and the five is the base. All you do is 5 x 5 x 5 x 5 x 5 x 5 x 5 x 5 x 5 x 5 x 5 x 5 or five multiplied by itself 12 times.
(x^2 - 25)/(x + 5) = [(x - 5)(x + 5)]/(x + 5) = x - 5
Prime factors are 2, 2, 2, 2, 5, 5, 5, 7 Other factors are combinations, i.e. 2 x 2 = 4 2 x 5 = 10 2 x 7 = 14 5 x 5 = 25 5 x 7 = 35 2 x 2 x 2 = 8 2 x 2 x 5 = 20 2 x 2 x 7 = 28 2 x 5 x 5 = 50 2 x 5 x 7 = 70 5 x 5 x 5 = 125 5 x 5 x 7 = 175 2 x 2 x 2 x 2 = 16 2 x 2 x 2 x 5 = 40 2 x 2 x 2 x 7 = 56 2 x 2 x 5 x 5 = 100 2 x 2 x 5 x 7 = 140 2 x 5 x 5 x 5 = 250 2 x 5 x 5 x 7 = 350 5 x 5 x 5 x 7 = 875 2 x 2 x 2 x 2 x 5 = 80 2 x 2 x 2 x 2 x 7 = 112 2 x 2 x 2 x 5 x 5 = 200 2 x 2 x 2 x 5 x 7 = 280 2 x 2 x 5 x 5 x 5 = 500 2 x 2 x 5 x 5 x 7 = 700 2 x 5 x 5 x 5 x 7 = 1,750 2 x 2 x 2 x 2 x 5 x 5 = 400 2 x 2 x 2 x 2 x 5 x 7 = 560 2 x 2 x 2 x 5 x 5 x 5 = 1,000 2 x 2 x 2 x 5 x 5 x 7 = 1,400 2 x 2 x 5 x 5 x 5 x 7 = 3,500 2 x 2 x 2 x 2 x 5 x 5 x 5 = 2,000 2 x 2 x 2 x 2 x 5 x 5 x 7 = 2,800 2 x 2 x 2 x 5 x 5 x 5 x 7 = 7,000
1,000,000,000 = 109 = (2 x 5)9 = 29 x 59 = 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 5 x 5 x 5 x 5 x 5 x 5 x 5 x 5 x 5 The factors of one billion are 2 and 5
2 x 2 x 2 x 2 x 2 x 5 x 5 x 5 x 5 x 5
To find the factors of a number, start with its prime factors. In the case of 2000, these are 2 x 2 x 2 x 2 x 5 x 5 x 5. Multiplying different combinations of these gives us the whole list of factors: 1 22 x 2 = 42 x 2 x 2 = 82 x 2 x 2 x 2 = 1655 x 5 = 255 x 5 x 5 = 1252 x 5 =102 x 5 x 5 = 502 x 5 x 5 = 2502 x 2 x 5 = 202 x 2 x 5 x 5 = 1002 x 2 x 5 x 5 x 5 = 5002 x 2 x 2 x 5 = 402 x 2 x 2 x 5 x 5 = 2002 x 2 x 2 x 5 x 5 x 5 = 10002 x 2 x 2 x 2 x 5 = 802 x 2 x 2 x 2 x 5 x 5 = 400[2 x 2 x 2 x 2 x 5 x 5 x 5 = 2000] So you're quite right, 2000 does have 20 factors.