find the sum of the digits of the product:
2^1998 times 5^2001--------- how do i do it without a calculator???
2006-09-06 11:36:01 · 5 answers · asked by booBOO 1 in Science & Mathematics ➔ Mathematics
2^1998*5^2001 = 10^1998 * 5^3 = 125 followed by 1998 zeroes. So the sum is 1+2+5+0*1998= 8
2006-09-06 11:40:38 · answer #1 · answered by maegical 4 · 0⤊ 0⤋
2^1998 times 5^2001
2^1998 times 5^1998*5^3
When powers are equal then bases are multiplied
(2*5)^1998*125
10^1998*125
125 times 10^1998
12500000..................... 1998 times zeros
Therefore number of digits will be 2001
2006-09-06 18:49:09 · answer #2 · answered by Amar Soni 7 · 0⤊ 0⤋
combine terms, use rules for exponents.
Most of the digits turn out to bo zero.
I get 8 as the answer, but don't forget to show your work!
2006-09-06 18:47:01 · answer #3 · answered by bubsir 4 · 0⤊ 0⤋
http://mathworld.wolfram.com/
http://www.math.com
2006-09-06 19:13:58 · answer #4 · answered by Life after 45 6 · 0⤊ 0⤋
god i DON'T miss school!
2006-09-06 18:41:15 · answer #5 · answered by Anonymous · 0⤊ 0⤋