 # Adding and Subtracting Rules. When adding or subtracting numbers that have the same sign, you add the numbers together and keep the sign. 3 + 5 = 8 7.

## Presentation on theme: "Adding and Subtracting Rules. When adding or subtracting numbers that have the same sign, you add the numbers together and keep the sign. 3 + 5 = 8 7."— Presentation transcript:

When adding or subtracting numbers that have the same sign, you add the numbers together and keep the sign. 3 + 5 = 8 7 + 15 = 22 - 2 – 12 = - 14 - 15 – 16 = - 31

When adding or subtracting numbers that have opposite signs, you subtract the numbers and keep the sign of the larger number -5 + 10 = 5 12 – 7 = 5 -15 + 3 = - 12 – 2 + 9 = 7

Associative Laws The "Associative Laws" say that it doesn't matter how we group the numbers (i.e. which we calculate first)...when we add (a+ b) + c = a + (b + c)

Distributive Law The "Distributive Law" is the BEST one of all, but needs careful attention Try the calculations yourself: 3 × (2 + 4) = 3 × 6 = 18 3×2 + 3×4 = 6 + 12 = 18 Either way gets the same answer

Commutative Laws The "Commutative Laws" say we can swap numbers over and still get the same answer... a + b = b + a

Inverse Operation The operation that reverses the effect of another operation. Example: Addition and subtraction are inverse operations Another Example: Multiplication and division are inverse operations.

Download ppt "Adding and Subtracting Rules. When adding or subtracting numbers that have the same sign, you add the numbers together and keep the sign. 3 + 5 = 8 7."

Similar presentations