Minecraft: Swapping two scoreboard values

Solution 1:

This can be accomplished using /scoreboard players operation:

/scoreboard players operation <target1> <objective1> <operation> <target2> <objective2>

The available operations are:

• += Addition: increase first first score by second
• -= Subtraction: decrease first first score by second
• *= Multiplication: multiply the first score by the second
• /= Integer Division: divide first score by second
• %= Modular Division: set first score to the remainder when it's divided by the second
• = Assign: set first score to the second
• < Min: set first score to the min of either score
• > Max: set first score to the max of either score
• >< Swap: swaps the scores around

What you want to do should be:

/scoreboard players operation @p Reg1 = @p Reg2