It's the problem or problems in the story.
Answer:
railway cottages" are small workers' houses, originally built by railway companies for their employees (most likely in Victorian times). They tend to be near railway stations (but not in them) and railway lines, not surprisingly, and may even have a street address such as "3 Railway Cottages". They will all have been sold off on the private market, in most cases a long time ago, or bought up as social housing by local governments, so anyone may now live in them.
Explanation:
First add the whole numbers.
Then find the LCM (least common multiple) of 3 and 2, which are the denominators of both fractions. In this case, the LCM of 3 and 2 are 6.
As you can see in the photo, I multiplied a number than can result in 6 in both denominators. Then multiply that same number to the numerators.
Finally, add 21+2, but keep the denominator as 6.
This is how I learned it, hope it helps.