Solve: (-12¼) - (-8²/₇) Mixed Number Subtraction with Negatives

Question

(1214)(827)= (-12\frac{1}{4})-(-8\frac{2}{7})=

Video Solution

Solution Steps

00:00 Solve
00:04 Negative times negative is always positive, so we subtract
00:11 Multiply each fraction by the second denominator to find a common denominator
00:29 Convert to a larger mixed fraction
00:41 And this is the solution to the question

Step-by-Step Solution

Let's solve the problem step-by-step:

  • Step 1: Convert mixed numbers to improper fractions.

For 1214-12\frac{1}{4}, convert to an improper fraction:

1214=(12+14)=(484+14)=494-12\frac{1}{4} = -\left(12 + \frac{1}{4}\right) = -\left(\frac{48}{4} + \frac{1}{4}\right) = -\frac{49}{4}

For 827-8\frac{2}{7}, convert to an improper fraction:

827=(8+27)=(567+27)=587-8\frac{2}{7} = -\left(8 + \frac{2}{7}\right) = -\left(\frac{56}{7} + \frac{2}{7}\right) = -\frac{58}{7}

  • Step 2: Subtract the second improper fraction from the first.

The operation becomes 494(587)-\frac{49}{4} - (-\frac{58}{7}), which simplifies to 494+587-\frac{49}{4} + \frac{58}{7}.

Find a common denominator for 494\frac{49}{4} and 587\frac{58}{7}. The least common denominator is 28.

Convert 494-\frac{49}{4} and 587\frac{58}{7} to equivalents with a denominator of 28:

494=49×74×7=34328-\frac{49}{4} = -\frac{49 \times 7}{4 \times 7} = -\frac{343}{28}

587=58×47×4=23228\frac{58}{7} = \frac{58 \times 4}{7 \times 4} = \frac{232}{28}

So, 494+587-\frac{49}{4} + \frac{58}{7} becomes:

34328+23228=343+23228=11128-\frac{343}{28} + \frac{232}{28} = \frac{-343 + 232}{28} = \frac{-111}{28}

  • Step 3: Simplify the improper fraction 11128\frac{-111}{28} to a mixed number form.

Divide 111-111 by 28, which gives 3-3 and a remainder of 27. Thus:

32728-3\frac{27}{28}

Therefore, the solution to the problem is 32728-3\frac{27}{28}.

Answer

32728 -3\frac{27}{28}