Math 7 · Unit 4, Lesson 5: Fraction and Decimal Coefficients · Tile 2 of 3
Decimal Coefficients
Line up the decimals and keep the signs
Line up the decimals and keep the signs
With decimals, combine like terms the same way, and line up the decimal points when you add or subtract the coefficients. Change every subtraction to adding the opposite first, so you don't lose a negative.
−3.75 + 2(−4x + 6.1) − 3.25x−3.75 + −8x + 12.2 + −3.25x expand, adding the opposite(−8x + −3.25x) + (−3.75 + 12.2) move like terms together−11.25x + 8.45
Which are equivalent to −3.75 + 2(−4x + 6.1) − 3.25x?
A. 7x − 2x + 8.1B. 8.45 − 8x − 3.25xC. −1.75 − 7.25x + 6.1D. −11.25x + 12.2 − 3.75
Answer: B and D. A simplifies to 5x + 8.1 and C to −7.25x + 4.35, so they are not equivalent.
Elle and Finn
ElleMath-speak
Expressions with decimal coefficients are simplified with the same properties of operations.
FinnPlain English
Decimals don't change the rules. They just mean you line up the dots before you add.
NC standards: NC.7.EE.1, NC.7.NS.1.
Where to go next
Let me try a few6 problems on decimal coefficients.
Next: Tile 3, Fractions Outside the ParenthesesHand out a fraction
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