How many six digit number can be made from the digits 1, 1, 1, 2, 2, 3?

The permutation of all digits is [latex]6![/latex], but we don't differentiate the same digits, so we divide it by the number of permutations of 1's ([latex]3![/latex]) and 2's ([latex]2![/latex]) [latex]\dfrac{6!}{3!2!}=\dfrac{4\cdot5\cdot6}{2}=60[/latex]