B.5.RC:4.4 - Work the small case forward

Begin with the available inputs. Apply an operation when its prerequisites and conditions hold, retaining the output needed by later operations. At an unfamiliar transition, write, draw or perform enough of it to see what changes.

If the construction uses a notation you can read but cannot operate with, use A.6.3.RT to prepare a usable expression under its rules. If interpreting the notation itself remains the difficulty, obtain that missing preparation. A more legible expression helps only when it preserves the relation required by the operation.

Where an operation admits several outputs, select one that permits the intended continuation. If the source only guarantees that some suitable object exists, determine whether its account also provides a way to obtain the instance your next use needs.

Retain the difference between the construction being described and the particular trial. One successful trial can reveal the method and expose a gap. A claim about a whole class of inputs additionally needs the argument or other subject support appropriate to that claim.