If you were asked to send a written rule to a really smart young person learning this for the first time, what would you write to them?

• \(2+4=6\)
• \(-3-5=-8\)
• \(10+10=20\)
• \(1+0=1\)
• \(-7-7=-14\)
• \(-4-9=-13\)

These are all correct. What's the pattern?

• \(10-4=6\)
• \(3-5=-2\)
• \(10-10=0\)
• \(3-9=-6\)
• \(-4+15=11\)
• \(4-15=-11\)