54+21 break up both numbers

To break up the numbers 54 and 21, you can separate each number into its individual digits. Let's do that:

For 54:
5 + 4

For 21:
2 + 1

Now we can add the separate digits together:

5 + 4 = 9

2 + 1 = 3

Finally, we can add the results together:
9 + 3 = 12

So, 54 + 21 equals 12.