How to make a 10Mz to 1Mz frequency divider using J-K flop flops?

Answer 1

Look on page 4 of this PDF file for the 7490 decade counter. The diagram uses J-K flops and one R-S flop (but you can wire a J-K to be an R-S):
http://focus.ti.com/lit/ds/symlink/sn7490a.pdf

Then, just wire is up as as if it were a 7490-divide-by-10 (also given in the data sheet)

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Answer 2

I would probably use a 4 bit register, take the output of the 1 side of 2 & 8 AND them together. Use the same signal to clear all flops at the same time you get the 10 output. That would put 1 pulse out for every 10 input and by using the same signal as a clear pulse it would eliminate most of the square portion of the output.