To add 4м 45см and 4м 56см, you would first add the meters together and then add the centimeters together.

4м + 4м = 8м
45см + 56см = 101см
Since 100 centimeters is equivalent to 1 meter, we can convert 101см to 1м 1см.

Now we have:
8м + 1м = 9м
1см

Next, to subtract 2м 43см from 10м, we would subtract the meters and then subtract the centimeters.

10м - 2м = 8м
0см - 43см is not possible, so we need to borrow 1 meter from the 8 meters, making it 7 meters and adding 100 centimeters to the centimeter total.

10м = 7м 100см
7м - 2м = 5м
100см - 43см = 57см

Therefore, the final answer is 5м 57см.