Bridget added 1/5 to both 12 and 6 4/5 when subtracting 12 - 6 4/5. Tell why.

To understand why Bridget added 1/5 to both 12 and 6 4/5 when subtracting 12 - 6 4/5, let's break down the process step-by-step:

Step 1: Subtraction
To subtract mixed numbers (like 12 - 6 4/5), we need to convert them into improper fractions.

12 can be written as 12/1, and 6 4/5 can be written as (6*5 + 4)/5 = 34/5.

Now we have 12/1 - 34/5.

Step 2: Common Denominator
To subtract fractions, we need a common denominator. In this case, the least common multiple (LCM) of 1 and 5 is 5.

So, we convert both fractions to have a denominator of 5:
12/1 * 5/5 = 60/5, and 34/5.

Now we have 60/5 - 34/5.

Step 3: Subtracting Fractions
To subtract fractions with the same denominator, we subtract their numerators and keep the common denominator.

60/5 - 34/5 = (60 - 34)/5 = 26/5.

Step 4: Mixed Number
To convert the resulting fraction (26/5) into a mixed number, we divide the numerator (26) by the denominator (5) and express the remainder as an improper fraction.

26 รท 5 = 5 with a remainder of 1.
So, the mixed number is 5 1/5.

Now, why did Bridget add 1/5 to both 12 and 6 4/5?

Bridget added 1/5 to both numbers to ensure that the subtraction of fractions (specifically, 34/5 from 60/5) would result in a proper fraction. By adding 1/5 to both 12 and 6 4/5, the resulting fraction would be 26/5, which can be expressed as the mixed number 5 1/5. This makes the subtraction operation more straightforward and gives a clear answer.

watch this.

a-b
(a+c)-(b+c) that is what she did. Is it ok?
a+c-b-c= original problem a-b