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Math 50

2.2 - Adding Integers

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Ex 1.Suppose you have $150 of debt on a credit card. If you used the card to pay for a $100 textbook, what would the balance be on your card? How could you write this as a number sentence using negative numbers?

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Ex 1.Suppose you have $150 of debt on a credit card. If you used the card to pay for a $100 textbook, what would the balance be on your card? How could you write this as a number sentence using negative numbers?

−$𝟐𝟓𝟎

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Ex 1.Suppose you have $150 of debt on a credit card. If you used the card to pay for a $100 textbook, what would the balance be on your card? How could you write this as a number sentence using negative numbers?

−$𝟐𝟓𝟎 (that is, of debt)

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Ex 1.Suppose you have $150 of debt on a credit card. If you used the card to pay for a $100 textbook, what would the balance be on your card? How could you write this as a number sentence using negative numbers?

−$𝟐𝟓𝟎 (that is, of debt)

−𝟏𝟓𝟎+(−𝟏𝟎𝟎)=−𝟐𝟓𝟎

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Ex 1.Suppose you have $150 of debt on a credit card. If you used the card to pay for a $100 textbook, what would the balance be on your card? How could you write this as a number sentence using negative numbers?

−$𝟐𝟓𝟎 (that is, of debt)

−𝟏𝟓𝟎+(−𝟏𝟎𝟎)=−𝟐𝟓𝟎

add of debt

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Ex 2.Suppose you have $150 of debt on a credit card. If you made a payment of (i.e. credit the card for) $80, what would the balance be on your card?

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Ex 3.Suppose you have $150 of debt on a credit card. If you made a payment of (i.e. credit the card for) $170, what would the balance be on your card?

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If _______ sign, _______ their absolute values and keep same sign.ex:

If ____________ signs, ______________ their absolute values and keep sign of number with greater absolute value.ex: and

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If _______ sign, _______ their absolute values and keep same sign.ex:

If ____________ signs, ______________ their absolute values and keep sign of number with greater absolute value.ex: and

same

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If _______ sign, _______ their absolute values and keep same sign.ex:

If ____________ signs, ______________ their absolute values and keep sign of number with greater absolute value.ex: and

same add

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If _______ sign, _______ their absolute values and keep same sign.ex:

If ____________ signs, ______________ their absolute values and keep sign of number with greater absolute value.ex: and

same add

different

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If _______ sign, _______ their absolute values and keep same sign.ex:

If ____________ signs, ______________ their absolute values and keep sign of number with greater absolute value.ex: and

same add

different subtract

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Ex 4.

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When adding many integers, it is easier to add positive and negative numbers separately:

Ex 5.

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Two numbers that ______ to ___ are called __________________________.

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Two numbers that ______ to ___ are called __________________________.

add

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Two numbers that ______ to ___ are called __________________________.

add 𝟎

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Two numbers that ______ to ___ are called __________________________.

add 𝟎additive inverses

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Two numbers that ______ to ___ are called __________________________.

add 𝟎additive inverses

ex: 5 and are additive inverses since

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Ex 6.Find the additive inverse of 6. Ex 7.Find the additive inverse of .

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Ex 6.Find the additive inverse of 6. Ex 7.Find the additive inverse of .

−𝟔

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Ex 6.Find the additive inverse of 6. Ex 7.Find the additive inverse of .

−𝟔

𝟑

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Note: The minus sign (—) can mean:

1. Subtract ex: “seven minus two”

2. Negativeex: “negative three”)

3. Additive inverseex: “the additive inverse of negative three”)