10 9/10 - -3.5

1 answer

To subtract -3.5 from 10 9/10, first convert the mixed number and the decimal to a common form.

  1. Convert the mixed number 10 9/10 to an improper fraction:

    • The whole number part (10) can be converted to a fraction: \( 10 = \frac{10 \times 10}{10} = \frac{100}{10} \).
    • Add the fractional part: \[ 10 9/10 = \frac{100}{10} + \frac{9}{10} = \frac{109}{10} \]
  2. Convert -3.5 to a fraction:

    • The decimal -3.5 can be expressed as: \[ -3.5 = -\frac{35}{10} \]
  3. Subtract the fractions:

    • We need to subtract -3.5 (which is -35/10) from 10 9/10 (which is 109/10). Since subtracting a negative is the same as adding: \[ 10 9/10 - (-3.5) = \frac{109}{10} + \frac{35}{10} \]
  4. Combine the fractions: \[ \frac{109 + 35}{10} = \frac{144}{10} \]

  5. Convert the improper fraction back to a mixed number:

    • Divide 144 by 10, which equals 14 with a remainder of 4. Therefore: \[ \frac{144}{10} = 14 \frac{4}{10} = 14 \frac{2}{5} \text{ (simplifying } \frac{4}{10}\text{)} \]

Thus, \( 10 9/10 - (-3.5) = 14 \frac{2}{5} \).