standard_description: Add and subtract fractions with unlike denominators (including mixed numbers) by replacing given fractions with equivalent fractions in such a way as to produce an equivalent sum or difference of fractions with like denominators. For example, 2/3 + 5/4 = 8/12 + 15/12 = 23/12. (In general, a/b + c/d = (ad + bc)/bd.)
problem_activity: Problem 1
A dime is
$${{1\over10}}$$
of a dollar and a penny is
$${{1\over100}}$$
of a dollar.
Would you rather have 4 one-dollar bills and 1 dime, 42 dimes, or 413 pennies? Justify your answer.
Problem 2
a.   Decide whether each of these has the same value as 3.57. Explain your reasoning.
357 tenths
357 hundredths
3 ones 57 tenths
3 ones 57 hundredths
34 tenths 17 hundredths
3 ones 7 hundredths 5 tenths
b.   Find as many ways as you can to make
$$2 \frac{4}{10}$$
using ones, tenths, and hundredths. If you think you have found all the ways, explain how you know your list is complete.
Problem 3
a.   What number represents the same amount as 1 one 70 hundredths?
b.   What number represents the same amount as 40 tenths 9 hundredths?
c.   What number represents the same amount as 268 hundredths?
d.   What number represents the same amount as 2 ones 14 tenths?
e.   What number represents the same amount as 3 ones 16 tenths 25 hundredths?


aligns: no