We can use the associative property to write 70 as 7*10. We can do this same process to write 6000 as 6*1000. This gives us:
(7*10)*(6*1000)
Using the commutative property, we can rearrange the factors of this problem
(7*6)*(10*1000)
7*6 is in our multiplication tables, and we know that powers of 10 allow us to just add the correct number of zeros. This means we would have 7*6=42, and have 4 zeros, for 420000.
