Math easy fractions explain how u did it step by step

678 51/68 - 676 65/78=????

make each an improper fraction 678*68+51=46155/68-676*78+65=52793/78
46155/68-52793/78 find common denominators
The LCD is 2652 so 46155*39=1800045/2652
52793*34=1794962/2652
your new equation is 1800042/2652-1794962/2652
so 1800042-1794962=5080/2652= keep reducing until you get 1270/663= 1 607/663 pretty sure thats as low as you can go

When subtracting mixed numbers, subtract the whole numbers to get the whole number in the answer, and do the same for the numerators, if the denominators are already the same.

In this case, first get the denominators the same.
You can find the least common denominator using the prime factorizations of 68 and 78 (breaking each down into its prime factors, as a product).
68 = 17*2*2
78 = 13*3*2
The least common multiple of these must include as factors: 17, 13, 3 (each of those once) and two 2's (2 appears twice for one of the numbers).
LCD = 17*13*3*2*2 = 2,652
2,652÷68 = 39, so multiply 51/68 by 39/39.
2,652÷78 = 34, so multiply 65/78 by 34/34.

Once you have the same denominator for both fractions:
If the numerator in the first number is less than that in the second number:
Rewrite the first number:
--- Add 1 in fraction form to the fraction part.
--- Subtract 1 from the whole number part.