If you take all the prime numbers less than 1,000,000 and multiply them together, what will be the last digit of the answer?????(Headbang)(Headbang)(Headbang)(Headbang )(Headbang)(Headbang)(Headbang)

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- Nov 5th 2008, 11:02 AMhelp123Bonus problems need it done by TOMMOROW!!
If you take all the prime numbers less than 1,000,000 and multiply them together, what will be the last digit of the answer?????(Headbang)(Headbang)(Headbang)(Headbang )(Headbang)(Headbang)(Headbang)

- Nov 5th 2008, 06:20 PMSoroban
Hello, help123!

Did you even**try**?

Quote:

If you take all the prime numbers less than 1,000,000 and multiply them together,

what will be the last digit of the answer?

The primes are: . 2, 3, 5, 7, 11, . . .

Start mutiplying . . .

. . $\displaystyle \begin{array}{ccc}2 \times 3 &=& 6 \\

\times 5 &=& 30 \\ \times 7 &=& 210 \\ \times 11 &=& 2310 \\

\vdots & & \vdots \\ & & duh!\end{array}$

- Nov 6th 2008, 11:51 AMhelp123
thank you thank you