Question 760064
(1)
4 math books:
{{{ 4*3*2*1 = 24 }}}
6 physics books:
{{{ 6*5*4*3*2*1 = 720 }}}
5 chemistry books:
{{{ 5*4*3*2*1= 120 }}}
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There are {{{ 3*2*1 = 6 }}} different
ways to arrange these 3 groups of books
{{{ 6*24*720*120 = 12441600 }}}
There are 12,441,600 ways to arrange the books
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(2)
Math books are together
4 math books:
{{{ 4*3*2*1 = 24 }}}
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The total of the other books is {{{ 6 +5 = 11 }}}
You can think of this as 12 items: the group of 
math books and each of the other books
{{{ 24*11*10*9*8*7*6*5*4*3*2*1 }}}
Can't do this on my cheap calculator