The most common and most likely answer to this crossword clue is the 5 plus 4 letter word SLIDE RULE
I've seen this crossword clue in The Guardian
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More clues leading to the result SLIDE RULE
- As plaything, order calculator
- One can work things out using this playground equipment control
- Old-school computer – might it read “use only in sedentary position”?
- Old mathematical aid for control of luge?
- Calculation device I’ll use, designed to impress friends occasionally around
- Drop protocol to obtain an analog computer
- Slip by government calculator
Buddy explains!
The straight part
We know that "One can work things out using this" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one can work things out using this = slide rule.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.