The problem consists of two parts. The first part requires us to calculate the total number of children who went sailing in May, June, and July. The second part requires us to find the difference between the number of children who went walking and climbing in June.

1. Problem Description

The problem consists of two parts.

The first part requires us to calculate the total number of children who went sailing in May, June, and July.

The second part requires us to find the difference between the number of children who went walking and climbing in June.

2. Solution Steps

For the first part:

We need to find the number of children who went sailing in each month:

May: 15

June: 42

July: 50

The total number of children who went sailing in May, June, and July is $15 + 42 + 50$.

$15 + 42 + 50 = 57 + 50 = 107$

For the second part:

We need to find the number of children who went walking and climbing in June:

Walking in June: 80

Climbing in June: 27

The difference is $80 - 27$.

$80 - 27 = 53$

3. Final Answer

The number of children who went sailing in May, June, and July is

1

0

7. The difference between the number of children who went walking and climbing in June is 53.