Jeanine used 21/2 cups of flour to make muffins and 1 3/4 cups of flour to make biscuits. After borrowing 1/4 cup of flour,she had 2 1/4 cups left to make bread. How much flour did she have to begin with?

2.5 + 1.75 + 2.25 - 0.25 = ?

To find out how much flour Jeanine had to begin with, we need to add up the amounts of flour she used for the muffins, biscuits, and the amount she had left for the bread.

For the muffins, Jeanine used 21/2 cups of flour.
For the biscuits, she used 1 3/4 cups of flour.
For the bread, she had 2 1/4 cups of flour left.

To add these amounts, we need to make sure they have the same denominator. In this case, the lowest common denominator is 4. Let's convert all the fractions to have a denominator of 4:

21/2 cups of flour is the same as 20/4 cups of flour (dividing the numerator 21 by 2 and multiplying the denominator 2 by 2).
1 3/4 cups of flour is the same as 7/4 cups of flour (multiplying the whole number 1 by the denominator 4 and adding the numerator 3).

Now, we can add up the amounts of flour Jeanine used:

20/4 + 7/4 = 27/4

Next, we need to subtract the amount of flour she borrowed, which is 1/4 cup:

27/4 - 1/4 = 26/4

Finally, to find out how much flour Jeanine had to begin with, we need to convert the fraction back to a mixed number:

26/4 = 6 2/4

Since 2/4 is equal to 1/2, the amount of flour Jeanine had to begin with is 6 1/2 cups.