Juanita ran 8.3 miles in Week 1 and 12.09 miles in Week 2. She used the subtraction below to determine how much farther she ran in Week 2 than in Week 1.
12.09 minus 8.30 = 4.79. All decimals are aligned. The 0 in 12.09 is crossed out and a 1 is above it. The 2 is crossed out in 12.09 and a 1 is above it.
Which error did Juanita make?
She subtracted instead of added.
She aligned the decimal points incorrectly.
She did not regroup correctly when subtracting.
She made a computational error when subtracting.
