4 ten thousands is the same as how many tens.
=> Okay, let’s do this:
=> Let’s first show the scientific notation of the given number
=> how many tens are there in 10 000 (10 000 / 10) = 1000
Thus there are 1000 tens in 10 000
=> 10 x 10 = 100 * 10 = 1000 * 10 = 10 000
=> 4 x 10^4
Let’s try checking if we have the correct answer
=> 4 x 10 000
=> 40 000