To showroom two fractions they must be over a common denominator, which for this problem is #10#.

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To put each fraction over a common denominator we must multiply each fraction by the appropriate form of #1#:

#2/5 + một nửa => (2/2 xx 2/5) + (5/5 xx 1/2) => 4/10 + 5/10#

We can now địa chỉ cửa hàng the numerators of the two fractions over the common denominator:

#4/10 + 5/10 => (4 + 5)/10 => 9/10#



You need a "common denominator": the number at the bottom of each fraction must be the same. Khổng lồ get that, we can multiply a fraction by #x/x#, where #x# is any number, since #x/x=1#.

Since our denominators are 2 & 5, we need a common denominator that both of those will divide into equally. I"m going to choose 10. It"s true that đôi mươi or 100 or 1 000 000 would also work, but we usually try to lớn use the "least common denominator" or "lowest common denominator" (both are abbreviated as LCD).

To get #2/5# khổng lồ have 10 as the denominator, I will multiply it by #2/2#, & get #4/10#. (we"ve really just multiplied it by 1, since #2/2 = 1#)

To get #1/2# khổng lồ have 10 as the denominator, I will multiply it by #5/5#, and get #5/10#.

Now we can địa chỉ cửa hàng the two fractions: #4/10 + 5/10 = 9/10#.

We can"t simplify that any further, so #9/10# is our answer.


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vanessa
Jun 11, 2017

Start by finding the least common multiple of 5 and 2, the denominators. Their lcm is 10. Now we have khổng lồ make the denominators both 10.

#2/5*2/2#

Since 2/2 is one, you aren"t really changing the fraction. Either way, we end up with

#4/10# as our first fraction. Now for the second one, we make its denominator 10 as well, by multiplying by 5/5. Since 5/5=1, the fraction isn"t changing.

#1/2*5/5#

The final fraction is 5/10. Now that the denominators are the same, simply địa chỉ the numerators và simplify the fraction.

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#(5+4)/10# => #9/10#

However, the greatest common multiple of 9 and 10 is 1, so the fraction can"t be simplified and #9/10# is the final answer.


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