Base 4 Numbers
af Allison Lindhorst

1. Most Difficult
1.1. Base 4 pieces
1.2. Subtraction
1.3. Multiplication
1.4. Division
1.4.1. Remainders
2. Closed?
2.1. Addition
2.1.1. Yes?
2.1.2. No?
2.2. Subtraction
2.2.1. Yes?
2.2.2. No?
2.3. Multiplication
2.3.1. Yes?
2.3.2. No?
2.4. Division
2.4.1. Yes?
2.4.2. No?