What number has the same value as 50 tens? ?

50 tens is the same as saying 50 x 10 which is 500.

One ten is 10.  Therefore, to find 50 tens, you must times 50 by 10.  When multiplying a number greater than 0 by 10, you simply add a 0 to the end of the number.  Following this rule, 50 tens is 500.