Students love to practice expanded form with these Color by Code math worksheets. I use them for morning work, math centers, spiral review homework, and pop them into sub plans for a guest teacher. There are six different designs included with colored answer keys. Each color within the design has several 3 digit numbers associated with it. Students solve for the 3 digit number then look up the color in the color key. Great for 2nd, 3rd and as an extension for 1st grade.