why can you not do this?
if you multiply 3 1/3 and 5 1/4 why when you do 3x5 =15 and (1/3)x(1/4)=(1/12) the answer is not 15 1/12
if you multiply 3 1/3 and 5 1/4 why when you do 3x5 =15 and (1/3)x(1/4)=(1/12) the answer is not 15 1/12
Morningfox
You also need to multiply 3 x 1/4, and 1/3 x 5.
So that is 3/4 and 5/3. When you add those to 15 1/12, you get the correct answer
15 & 1/12 + 3/4 + 5/3 = 17 & 1/2
Anonymous
3 1/3 can be written as 3 + 1/3
5 1/4 can be written as 5 + 1/4
When you multiply them together, you get:
(3 + 1/3)(5 + 1/4)
Note that this needs to be foiled out. Doing so gets you this:
3*5 + 3*1/4 + 1/3*5 + 1/3*1/4
15 + 3/4 + 5/3 + 1/12
35/2
It does NOT get you this:
3*5 + 1/3*1/4
?
(3⅓)(5¼) = (3 + ⅓)(5 + ¼)
By the distributive rule,
(3 + ⅓)(5 + ¼) = 3×5 + ⅓×5 + 3×¼ + ⅓×¼ = 15 + 5/3 + 3/4 + 1/12 = 17.5
Wile E.
3 1/3 x 5 1/4
When performing math operations
on proper fractions, first convert the
proper fractions to improper fractions.
3 1/3 = 10/3
5 1/4 = 21/4
Multiplying the numerators,
10 x 21 = 210
Multiplying the denominators,
3 x 4 = 12
Putting them together,
210/12
Converting back to proper fractions,
17 1/2
¯¯¯¯¯
Sarah
3 1/3 is (3+1/3)
5 1/4 is (5 + 1/4)
(3+1/3)(5+1/4) now you must foil.
3*5+3*1/4+1/3*5+1/4*1/3=35/2
Or you could expand the fractions.
3 1/3=10/3
5 1/4= 21/4
10/3*21/4=210/12 reduces to 35/2.
Hope this clarifies :)