Choose and perform a way to complete the current task

Six lots contain 347 items each. What total should we report? In this constructed case, a previous comparable check supports the person’s mental decomposition 350 × 6 − 3 × 6. No record of intermediate operations is required. Paper and a local calculator are available but must be taken out; the network is unavailable. The preference is to meet the correctness requirement with the least additional setup and working burden. These are supplied teaching conditions, not measurements of people’s speed or error rates.

C.38 makes the ways comparable. Mental work includes binding the numbers, calculating, checking the subtraction and reporting. Paper adds obtaining the sheet, aligning the digits and carries, calculating, checking and reading the result. Calculator use adds obtaining the device, entering and inspecting the expression, performing the operation, interpreting the display and reporting. Search lacks access. Comparing mental work with only a calculator’s button press would omit part of the supported way.

On the supplied evidence all three available ways meet the requirement. Paper and calculator add setup without a needed benefit here. C.11 applies the stated preference and chooses mental decomposition. C.11.CRC’s baseline, change and horizon questions reduce to the current person and means, opening another means, and this one result. There is no consequential unknown worth investigating. The person obtains 350 × 6 = 2100, subtracts 3 × 6 = 18, checks that this removes exactly the extra three items per lot, and reports six lots contain 2082 items. The receiving task is complete.

Change the record requirement. Suppose a later check requires recoverable intermediate digit operations. Mental computation alone and the simple calculator’s final display no longer suffice. Mental computation followed by a written account is another complete, mixed way. In this constructed comparison, a ready column layout has the least supported burden for both product and record. The chooser selects it. The person computes 7 × 6 = 42, writes 2 and carries 4; computes 4 × 6 + 4 = 28, writes 8 and carries 2; then computes 3 × 6 + 2 = 20. The answer is 2082 with aligned working. SYSE.52 prepares usable material; SYSE.43 retains it if later access needs a managed record. The person computes; paper preserves positions and carries. Keeping a carry digit while losing its column can defeat the next step.

Choose a worthwhile tool while still able to calculate unaided. Restore the original record condition. This time the calculator is already open and the person is holding other task-critical intermediate values. Comparable-use evidence supports reduced working burden, including input inspection and reading the display; the preference protects those values before avoiding a tool call. The chooser selects the calculator. The person enters 347 × 6, checks the displayed expression, obtains 2082 and reports it. SYSE.42 carries out that binding and result use. No learning programme or claim of incapacity follows.

If the device’s ability to show the entered expression is unknown and that fact could change the choice, a brief inspection can be worthwhile. Obtain that fact only when its effect on the decision warrants the interruption; otherwise use the already supported way. A functioning device given 374 × 6 returns 2244: repair the input and apply the receiving task’s check before using 2082. With network access restored, a search alternative must include access, submission, interpretation, checking and use. Establish whether the return is a computation, a cited page, a generated answer or an unrelated match. Two interfaces to one calculation service are not independent checks.

Repeated lost carries can justify a better layout or procedure. Later unaided multiplication is a different result: E.23.CDI and HCD supply practice, feedback and the later capability test. A correct calculator answer alone establishes neither that acquisition nor its absence. A person, the equipped performing arrangement, the tool and a record retain their distinct contributions.