Question 609908
This problem can be done two ways:<ul><li>Convert the base 7 numbers to base ten, multiply and then convert back to base 7; or<li><li>Try to do base 7 multiplication.</li></ul>I'm going to do the second one. The key is to carry when you get 7 or more instead of 10 or more when you multiply:
<pre>

  453
x   4
-----

4 x 3 is twelve which is a seven with 5 left over:

   1
  453
x   4
-----
    5

4 x 5 is twenty which is two sevens with 6 left over:

  21
  453
x   4
-----
   65

4 x 4 is sixteen which is 2 sevens with 2 left over:

 221
  453
x   4
-----
 2265
</pre>
So 453 base 7 times 4 base 7 is 2265 base 7