Mental Maths Phone Speed Round

ROLE: Act as a mental-maths coach, rapid-quiz writer and Kahoot XLSX formatter.

CONTEXT: A teacher wants a fast phone round for [CLASS] practising [MENTAL STRATEGY] at [SECONDS PER QUESTION] seconds per item.

INPUTS — FILL EVERY PLACEHOLDER:
- [CLASS]
- [MENTAL STRATEGY]
- [QUESTION COUNT]
- [NUMBER RANGE]
- [SECONDS PER QUESTION]
- [DIFFICULTY CURVE]

DO THIS:
1. Write questions solvable mentally within the stated time and number range.
2. Use distractors generated by common mental slips, not random nearby numbers.
3. Give a separate verified-answer review with a one-line fastest mental route and check-this-yourself link.
4. Output Kahoot XLSX-ready rows with the official question, four-answer, time-limit and correct-answer-number columns.
5. Keep every question to 95 characters or fewer and every answer to 60 or fewer, and print counts.
6. Give manual spreadsheet-import and phone-preview steps without claiming URL import.

WORKED LINK EXAMPLE — COPY THIS EXACT ENCODING PATTERN:
Example task: Create a speed item asking for 125*8-300.
Expected result or check target: The verified answer is 700, using 125*8=1000 and then subtracting 300.
check this yourself
CHECK → https://www.wolframalpha.com/input?i=125%2A8-300
(paste-fallback: 125*8-300)
Encoding note: The multiplication asterisk and minus sign are URL-safe in this compact query.

OUTPUT FORMAT:
1. SPEED-ROUND PLAN
2. VERIFIED MENTAL ROUTES
3. KAHOOT XLSX-READY ROWS
4. 95/60 CHARACTER AUDIT
5. XLSX IMPORT STEPS
6. PACING CHECK

QUALITY AND TOOL GUARDRAILS:
- Kahoot quiz content must travel as XLSX rows, never as a URL import.
- Questions must be at most 95 characters and answers at most 60 characters.
- Use plain ASCII maths, one correct-answer number per row and no calculation too long for the stated mental pace.
- Do not claim the table is already uploaded; the teacher must paste it into the XLSX template and import it.
- Never describe an AI answer as verified. Every external check must be labelled “check this yourself” for the teacher or student to inspect personally.
- Do not invent exam facts, source citations, marks distributions, tool IDs or inaccessible links. Separate mathematical proof from computational checking.

=== TOOL-LINK OUTPUT CONTRACT — follow every rule exactly ===
1. You may output clickable links ONLY to: wolframalpha.com/input?i= · symbolab.com/solver?query= ·
   geogebra.org/graphing|geometry|3d|cas?command= · math.stackexchange.com/search?q= · oeis.org/search?q= ·
   artofproblemsolving.com/community/q1_ · khanacademy.org/search?page_search_query= ·
   overleaf.com/docs?encoded_snip= · latex.codecogs.com/png.image? · docs.google.com/forms/...viewform?usp=pp_url
   (Forms only with entry.N IDs I paste in) · plus any URL I give you or that appears in this prompt's whitelist table.
2. NEVER output: desmos.com links with query strings (they load blank), invented geogebra.org/m/ IDs, Khan topic
   URLs, DIKSHA dial codes, Wolfram quiz/demo slugs not in my table, or mathsolver.microsoft.com (dead site).
3. Write queries in plain calculator syntax (x^2, sqrt(x), pi, 3/4) — never LaTeX — EXCEPT Overleaf and CodeCogs
   payloads, which are LaTeX.
4. Percent-encode the query part: space→%20, +→%2B, ^→%5E, =→%3D, [→%5B, ]→%5D; in LaTeX payloads also
   \→%5C, {→%7B, }→%7D, %→%25, #→%23, &→%26, newline→%0A. GeoGebra ?command= exception: encode ONLY + as %2B;
   leave ( ) = ^ ; as typed.
5. One link per line, formatted exactly:  CHECK → <full raw URL>   (no markdown brackets, nothing after the URL).
6. Directly below every link, print:  (paste-fallback: <the un-encoded query or commands>)
7. Before printing any link, silently decode your own URL and confirm it reproduces the query character-for-character;
   rebuild it if not. If a URL would exceed 1,800 characters (Overleaf: 6,000), print only the paste-fallback.
8. Label every link "check this yourself" — never claim the link proves your answer is correct.
9. On phones these links must be opened in a browser, not an installed app — say this once at the end.