Show this many (3 tens 4 ones) add (7) do you need to regroup? (yes no) how many in all

How is trading a ten for ones the same as trading ones for a ten ?

Working problems of this sort is not unlike addition using a soroban or abacus. Those devices have a limited number of unit beads and one or two 5-count beads to represent each digit.

To add 7 to 16, you recognize that 7 = 4+3, and 16+4 = 20. So,

16 + 7 = 16 + (4 + 3) = (16 + 4) + 3 = 20 + 3 = 23.

On a soroban, this might be a little different:

16 + 7 = (10 + 5+ 1) + (5 + 2) = (10 + 5 + 1) + ((10 - 5) + 2)

= (10 + 10) + (5 - 5) + 1 + 2 = 20 + 3

To add 7 to 16, you recognize that 7 = 4+3, and 16+4 = 20. So,

16 + 7 = 16 + (4 + 3) = (16 + 4) + 3 = 20 + 3 = 23.

On a soroban, this might be a little different:

16 + 7 = (10 + 5+ 1) + (5 + 2) = (10 + 5 + 1) + ((10 - 5) + 2)

= (10 + 10) + (5 - 5) + 1 + 2 = 20 + 3