Final answer:
When converting units, 10 hundredths is equal to 1 tenth, therefore regrouping 10 hundredths into tenths gives us b. 1 tenth as the result.
Step-by-step explanation:
When adding and regrouping in mathematics, specifically when converting from smaller to larger units, it is important to understand the relationship between the units. In this case, to regroup 10 hundredths into tenths, we must recognize that each tenth contains 10 hundredths.
By regrouping 10 hundredths we have exactly 1 tenth because 10 hundredths = 0.10 and 0.10 is equal to 1 tenth.
Thus, the correct answer to the question 'When adding, regroup 10 hundredths into tenths, what is the result?' is b) 1 tenth.