For Q15, did you notice that
- the parts of the questions were systematically simplified before we put the 2 major parts together to solve?
- when put together for the first time, brackets are used for each part? This will reduce the confusion, especially when we are to subtract one part from another.
- before answering to the questions, we tried to sieve out as much information from the question as possible? These are needed to use to solve the parts.
- the information are clearly 'labelled'? e.g. "Elsie's age". This helps to reduce confusion subsequently.