For subtracting integers, you have to add the opposite.

Eg. 7 - (-12) =19

For multiplying integers, if the signs are the same, the product is positive, if the signs are different, the

product will be a negative number.

Eg. 5 x (-10) = -50 -5 x (-10) = 50

Dividing has the same rule as multiplying.

Eg. 24~ (-6) = (-4) -24~ (-6) =4

For adding -1 crosses out +1.

Eg. 5 + (-2) =3