We have  \[\frac{(10r^3)(4r^6)}{8r^4}= \frac{40r^{3+6}}{8r^4} = \frac{40}{8}r^{3+6-4} = \boxed{5r^5}.\]
Question:
Simplify $\frac{(10r^3)(4r^6)}{8r^4}$.
Answer:
Let's think step by step.

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5r^5
Simplify $\frac{(10r^3)(4r^6)}{8r^4}$.
test