Adding and Subtracting Fractions, UNLIKE Denominators

When two fractions have unlike denominators, we can just add or subtract straight across.

• True

• False

Answer explanation

This is false. It will always be false. There is no circumstance where this would be true.

Tags

CCSS.7.NS.A.1C

We always add up or subtract denominators.

• True

• False

Answer explanation

Again, this is always going to be false. Once our denominators are like we leave them alone. We do not add or subtract them ever.

Tags

CCSS.4.NF.B.3C

CCSS.4.NF.B.3D

 $\frac{1}{3}+\frac{1}{3}=?$  First up, determine if they have denominators that are the same! Then, add up those numerators.

•  $\frac{2}{6}$  

•  $\frac{2}{3}$  

•  $\frac{1}{5}$  

Answer explanation

 $\frac{2}{3}$  is the only correct answer. 

Tags

CCSS.4.NF.B.3A

 $\frac{5}{7}-\frac{1}{7}=?$  Again, the first step is to determine if they have like denominators. Then subtract the numerators.

•  $\frac{4}{7}$  

•  $\frac{6}{7}$  

•  $\frac{4}{0}$  

Answer explanation

 $\frac{4}{7}$  is the only correct answer.

Tags

CCSS.4.NF.B.3C

CCSS.4.NF.B.3D

 $\frac{1}{5}+\frac{1}{3}=?\$  First things first, get LIKE denominators!

•  $\frac{2}{8}$  

•  $\frac{2}{3}$  

•  $\frac{8}{15}$  

Answer explanation

 $\frac{2}{8}$  is just adding across :(  $\frac{2}{3}$  is also incorrect. 

Tags

CCSS.5.NF.A.1

CCSS.5.NF.A.2

 $\frac{5}{8}+\frac{2}{3}=\ ?$  Find LIKE denominators FIRST! 

•  $\frac{31}{24}$  or  $1\ \frac{7}{24}$  

•  $\frac{7}{11}$  

•  $\frac{7}{24}$  

Answer explanation

Remember to look for answers that are improper. Convert them to mixed numbers.  $1\ \frac{7}{24}$  is the only correct answer. 

Tags

CCSS.5.NF.A.1

CCSS.5.NF.A.2

 $\frac{3}{5}-\frac{1}{2}=\ ?$  

•  $\frac{2}{3}$  

•  $\frac{1}{5}$  

•  $\frac{1}{10}$  

Answer explanation

 $\frac{1}{10}$  is the only correct answer. 

Tags

CCSS.7.NS.A.1C

 $1\ \frac{2}{5}-\frac{1}{6}=\ ?$  Convert that mixed number to an improper fraction before finding like denominators. 

•  $1\ \frac{1}{2}$  

•  $\frac{37}{30}$  or  $1\ \frac{7}{30}$  

•  $1\ \frac{3}{1}$  

Answer explanation

 $1\ \frac{7}{30}$  is the only correct answer.  $1\ \frac{3}{1}$  isn't even possible. Mixed numbers cannot have an improper fraction along with the whole number. 

Tags

CCSS.7.NS.A.1C

Write the following mixed number as an improper fraction.

 $3\ \frac{1}{3}$  

•  $\frac{7}{3}$  

•  $\frac{1}{2}$  

• 4

•  $\frac{10}{3}$  

Answer explanation

Multiply the denominator with the whole number. Add the numerator to that product. Place the answer over the original denominator.

  $\frac{10}{3}$  is the only correct answer. 

Convert the improper fraction to a mixed number.

 $\frac{16}{9}$  

•  $1\ \frac{7}{9}$  

•  $1\ \frac{1}{3}$  

•  $2\ \frac{5}{9}$  

• 7

Answer explanation

You can check your answer by converting it back to an improper fraction. 
 $1\ \frac{7}{9}$  is the correct answer.