To find the sum \( 0.75 + (-0.68) \), we can think of it as subtracting \( 0.68 \) from \( 0.75 \):
\[ 0.75 - 0.68 \]
Now, let's perform the subtraction step by step:
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Align the numbers:
\[ 0.75
- 0.68 \]
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Subtract the values:
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Start from the rightmost digit (hundredths place):
- \( 5 - 8 \) cannot be done, so we need to borrow 1 from the tenths place. This makes the tenths place \( 6 \) instead of \( 7 \) and changes the hundredths place to \( 15 \) (since we took 1 away).
- Now we calculate: \( 15 - 8 = 7 \).
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Move to the tenths place:
- We have \( 6 - 6 = 0 \).
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Finally, look at the units place (which is just 0 in this case):
- \( 0 - 0 = 0 \).
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So, the result of \( 0.75 - 0.68 \) gives us:
\[ 0.07 \]
Thus, the sum \( 0.75 + (-0.68) \) is:
\[ \boxed{0.07} \]
The correct answer is B: \( 0.07 \).