Number challenges
Four different number problems. Work each one through at your own pace, with hints when you want them.
Multiplication, digit reversal, cube roots and prime factors.
Smaller values and direct clues. Use careful reasoning you can build on.
4 questions · No time limit
Up to 3 optional hints per question.
Example
Example
128 × 12 = ?
Try a short method first. The full working appears after you answer.
Hints
Start with your own idea, or open one step at a time.
Worked solution
Four questions done.
0 of 4correct
Review your questions
The round could not load.
Reload this page to try again. Your unfinished round was not saved.
Reload practiceOptional and off by default. Share starts, completions, replays and error categories. For visits from ChatGPT, starts and completions can also include the first QuickenBrain page and broad country. No answers, drawings or names.
How this data is usedHow this practice works
Classic has one multiplication, one digit reversal, one cube root and one prime factor problem. Extended has digit constraints, missing square digits, missing cube digits and one rotating Classic problem. Both have no deadline, Quick working and up to three hints per question.
Enter a whole number and press Enter or choose Check answer. A correct answer earns one point; hints do not change the score. Showing the answer earns no point for that question.
After each answer, review the method and check. Finishing all four questions saves the round in your practice history. Ending early does not save it.
About this practice
Learn a method
Reconstruct from number cluesFour different number problems. Work each one through at your own pace, with hints when you want them.
Report a problem
Optional and off by default. Share starts, completions, replays and error categories. For visits from ChatGPT, starts and completions can also include the first QuickenBrain page and broad country. No answers, drawings or names.
How this data is used