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 Dec 7 2004, 11:31 PM
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 jellyfishing, jellyfishing  Group: Member Posts: 1,174 Joined: Oct 2004 Member No: 55,185  |
aaacch i don't get this math problem, i'm really stupid. it's a junior high problem, so maybe someone could help?
Claire finished her assignment early, so her teacher suggested that she find the last digit of the product 3 x 3 to third power x 3 to fifth......x 3 to nineteenth. The entire product was too big for her calculator, but she still found the last digit. What is the last digit? Explain how she determined her answer i know that if you add all the exponents, you'll get 3 to the 100th power, since 3+5+7+9+11+13+15+17+19=100 right (those are the exponent values...), so it'd be 3 to the 100th power. on my calc i got 5.153775207 to the 47th power.....what next?!?!!? sorry if this is in the wrong board...i saw someone ask for math help awhile back, so i figured it'd be OK 
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Dec 8 2004, 02:02 AM
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jellyfishing, jellyfishing Group: Member Posts: 1,174 Joined: Oct 2004 Member No: 55,185 |
QUOTE(uninspiredfae @ Dec 7 2004, 10:43 PM) It alternates between 1, 3, 9, 7. Just use a calculator and write out the numbers on a piece of paper. You'll see the pattern. Every 4th power has the same ending digit, which happens to be 1. By the way, it would be 1 instead of 3 because you start with 3^1 and then 4th power ends with 1. ooooh i think i see what you're saying. so the 3 to the 100th power ends with a one right? but did you just write it all out or use some sort of technique?? |
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Posts in this topic
pAtRiCk_sTar help! Dec 7 2004, 11:31 PM
Spirited Away QUOTE5.153775207 to the 47th power.....what next?... Dec 7 2004, 11:41 PM DaTru KataLYST do you mean to find the last digit of the product ... Dec 7 2004, 11:44 PM Spirited Away This page has something similar except with the nu... Dec 7 2004, 11:47 PM x_angawhomps I think the last digit is going to be 1.
Because... Dec 8 2004, 12:20 AM pAtRiCk_sTar oooh thanks, i get it now! Dec 8 2004, 01:15 AM jr0h im sick of math problems..sorry. hahah Dec 8 2004, 01:20 AM pAtRiCk_sTar wait, wouldn't the pattern alternate between 3... Dec 8 2004, 01:41 AM Spirited Away It alternates between 1, 3, 9, 7. Just use a calcu... Dec 8 2004, 01:43 AM DaTru KataLYST omg, you guys...i'm lost...=( why must math be... Dec 8 2004, 01:53 AM x_angawhomps QUOTE(pAtRiCk_sTar @ Dec 7 2004, 11:02 PM)ooo... Dec 8 2004, 02:16 AM pAtRiCk_sTar QUOTE(x_angawhomps @ Dec 7 2004, 11:16 PM)If ... Dec 8 2004, 02:30 AM angel-roh it would be so cool if we had a homework help foru... Dec 9 2004, 12:16 AM
Just_Dream Problem solved.
TOPIC CLOSED. Dec 9 2004, 12:19 AM |
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