45.3 m + 12.344 m + 1000m - 1.34 m = ________________________

is 1 056.304 m the answer?

I don't think so. If the 1000 has no period after it it has only 1 s.f. and the answer 1E3. If it has a period, the answer is 1056.

To get the answer to the equation 45.3 m + 12.344 m + 1000m - 1.34 m, you need to perform the addition and subtraction operations.

First, add the values for the meters together:
45.3 m + 12.344 m + 1000m - 1.34 m = 1056.304 m.

So, yes, the answer is 1056.304 m.