Order of operations

This browser will not save progress — private browsing or blocked site data. Every level still works, but stars will not be kept.

• 01 Advanced

  Five numbers, all four

  8 problems · 6 min
• 02 Advanced

  Five numbers, bigger

  8 problems · 8 min
• 03 Advanced

  Negative answers allowed

  8 problems · 6 min
• 04 Advanced

  Six numbers

  8 problems · 7 min
• 05 Advanced

  Six numbers with minus

  8 problems · 6 min
• 06 Advanced

  Six numbers, brackets

  8 problems · 9 min
• 07 Advanced

  Six numbers, all four

  8 problems · 9 min
• 08 Advanced

  Two-digit numbers

  8 problems · 9 min
• 09 Advanced

  Two-digit, six numbers

  8 problems · 10 min
• 10 Advanced

  Everything review

  8 problems · 9 min