Congratulations, you've reached the final level! Mixed Challenge is the ultimate test where we combine everything from addition and division to percentages and equations. Show what you've got and prove your math accuracy.

Equations can seem intimidating, but they're really just a way to solve a mystery. What is "x"? Here you are introduced to simple equations where you use logic and basic arithmetic to find the missing number. Your first step into algebra!

Spanish nouns in context from English—pages and chapters, parties, clocks, textiles, toothbrushes, soap, shirts, and gloves—built for phrase-level recognition.

Swedish nouns in context from English—pages and chapters, parties, clocks, textiles, toothbrushes, soap, shirts, and gloves—built for phrase-level recognition.

Master elements 97–108, focusing on synthetic and transuranium elements.

Explore elements 85–96, including the beginning of the actinide series and radioactive elements.