Given the task definition, example input & output, solve the new input case.
You are given a math word problem and you are supposed to apply addition or subtraction mathematical operators on the numbers embedded in the text to answer the following question and then only report the final numerical answer.
Example: Last year , 90171 people were born in a country , and 16320 people immigrated to it . How many new people began living in the country last year ?
Output: 106491
Total people living in the country = born - immigrated = 90171 - 16320 = 106491

New input case for you: Irwin 's family went on a camping trip in the mountains . On the first day , they hiked from their car to the campsite . First , they hiked 0.2 mile from the car to a stream , and 0.4 mile from the stream to a meadow . Then they hiked 0.1 mile from the meadow to the campsite . How many miles did Irwin 's family hike in all ?
Output:
0.7