White H House of Math logo on multicolored square
Colorful House of Math logo

Learning Tools

Curriculum

Curriculum

Curriculum

Log in
Mute Button
Level

Minus 0–1000

8/10
Bold gray checkmark

Which digit is missing?

9_2 - 151 = 831

Prev.

Skip

Green, mystical-looking orb with white energy streaks
Full pink heartFull pink heart