Answer:
1 11/12
Explanation:
Notice (right away) that the denominators of the fractions are different (4 and 3).
Identify the LCD: It is 12.
Convert the two given numbers to mixed numbers with LCD 12:
3 3/12
-1 4/12
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4/12 is greater in magnitude than 3/12, so we must 'borrow' from the digits' place. Recall that 1 = 12/12.
Then 3 3/12 = 2 15/12. -1 4/12 stays the same; it has LCD 12.
Then, perform the indicated subtraction:
2 15/12
-1 4/12
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1 11/12 (answer: this is the difference "3 1/4 less 1 1/3")