The first is 1, the left is 1, and the right is 7.

The second one goes up (9), 6 to the left and 4 to the right.

The third one goes up (6), left 1, and right 2.

The third one goes up 1, about (8).

The fourth one goes up to 1, or so (1 1).

Law: Up+Right-Left =7

Property 1

Adding (or subtracting) the same algebraic expression on both sides of the equation still holds.

If a=b

Then a+c=b+c

Attribute 2

When both sides of the equation are multiplied or divided by the same non-zero algebraic expression, the equation still holds.

If a=b

Then there is a c = b c

Or a÷c=b÷c (c≠0).