Base 4 Numbers
da 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?