Solve these fresh tasks without adding a new language feature. The first four revisit object construction, private state, independent instances and domain descriptions. Later tasks bring back the arithmetic and traversal details that still matter inside a class: widening before a large product, recognizing an exact positive batch, skipping closed slots and filtering positive adjustments.
Treat the method signature as a contract. Return arrays in the requested order, keep punctuation exact in a domain description and avoid changing a quantity before you know that the operation is valid. A sensible happy-path example is only the first check. Also try a zero change, a rejected negative input, an empty sequence and an endpoint value where the prompt allows them. Each task stands alone with new fictional inputs.