Unit 4: Add and Subtract negative numbers #1

1. First find a common denominator by listing some multiples of 3 and 4

   Multiples of 4: 4,8,12,16,20,24...

   Multiples of 3: 3,6,9,12,15,18,21...

   As you can see, number 12 repeats on both lists, so we choose number 12 as the common denominator

2. Make equivalent fractions so 12 is the new denominator.

3. Add the new fractions together (numerators only)

• First find a common denominator by listing some multiples of 2 and 3

  Multiples of 2: 2,4,6,8,10,12...

  Multiples of 3: 3,6,9,12,15,18,21...

  As you can see, number 6 and number 12 repeat on both lists, but we only choose the smallest one as the common denominator

• Next, change both fractions to 6ths using equivalent fractions.

• Finally, add the new fractions together (remember to only add the numerators).

​Subtracting Fractions works the same as adding...

1. Find a common denominator.

2. Make equivalent fractions.

3. Add the new numerators.

Multiple Choice

Positive + Positive = ??

• Positive
• Negative
• It Depends

Multiple Choice

Positive + Negative = ??

• Positive

• Negative

• It Depends on which has a greater absolute value

Multiple Choice

negative + Negative = ??

• Positive

• Negative

• It Depends

Multiple Choice

What must you have to add and subtract fractions?

• Common numerators
• Different numerators
• Different denominators
• Common denominators

Multiple Choice

$$\frac{2}{3}-\frac{1}{2}=$$  

• $$\frac{3}{7}$$  

• $$\frac{1}{6}$$  

• $$\frac{1}{5}$$  

• $$\frac{7}{6}$$  

Multiple Choice

$$\frac{2}{5}-\frac{3}{10}=$$  

• $$\frac{7}{10}$$  

• $$\frac{1}{10}$$  

• $$\frac{1}{5}$$   

• $$\frac{1}{15}$$  

Multiple Choice

$$\frac{1}{3}+\frac{5}{12}=$$  

• $$\frac{6}{12}$$  

• $$\frac{6}{15}$$  

• $$\frac{9}{12}$$  

• $$\frac{4}{4}$$  

Multiple Choice

$$\frac{3}{5}+\frac{1}{4}=$$  

• $$\frac{5}{20}$$  

• $$\frac{12}{20}$$  

• $$\frac{7}{20}$$  

• $$\frac{17}{20}$$  

Multiple Choice

$$\frac{2}{4}-\frac{3}{8}=$$  

• $$\frac{1}{8}$$  

• $$\frac{5}{4}$$

• $$\frac{4}{32}$$  

• $$\frac{1}{2}$$  

Multiple Choice

The Gill family ordered a large pizza. Kyle ate 1/8 of the pizza, Scott ate 2/8 of the pizza, and Missy ate 3/8 of the pizza. How much of the pizza was left?

Hint: The whole pizza was 8/8.

• $$\frac{8}{8}$$

• $$\frac{6}{8}$$

• $$\frac{3}{8}$$

• $$\frac{2}{8}$$

Multiple Choice

$$\frac{1}{3}+\frac{1}{6}=$$  

• $$\frac{4}{6}$$  

• $$\frac{5}{6}$$  

• $$\frac{1}{2}$$  

• $$\frac{2}{3}$$  

Multiple Choice

$$-\frac{3}{10}-\left(-\frac{2}{5}\right)$$  

• $$-\frac{1}{10}$$  

• $$\frac{1}{10}$$  

• $$\frac{7}{10}$$  

• $$-\frac{7}{10}$$  

Multiple Choice

$$-\frac{3}{7}+\frac{4}{5}$$

• $$\frac{43}{55}$$

• $$-\frac{13}{35}$$

• $$-\frac{43}{55}$$

• $$\frac{13}{35}$$

Multiple Choice

$$\frac{4}{9}+\left(-\frac{2}{3}\right)$$

• $$1\ \frac{1}{9}$$

• $$-1\ \frac{1}{9}$$

• $$\frac{2}{9}$$

• $$-\frac{2}{9}$$

Multiple Choice

$$\frac{2}{4}+\left(-\frac{5}{4}\right)$$

• $$-\frac{7}{4}$$

• $$\frac{3}{4}$$

• $$-\frac{3}{4}$$

• $$-\frac{7}{8}$$

Multiple Choice

$$-\frac{11}{12}-\left(-\frac{5}{12}\right)$$  

• $$-\frac{1}{2}$$  

• $$\frac{1}{2}$$  

• 16

• $$\frac{1}{24}$$