Word problems involving adding and subtracting fractions with a fun pizza theme.

1) The pizza is covered with mushrooms ($\frac{5}{16}$), onions ($\frac{1}{4}$), and cheese. To find the fraction covered with only cheese, subtract the fractions of mushrooms and onions from the whole pizza ($\frac{16}{16}$).

First, convert $\frac{1}{4}$ to sixteenths: $\frac{1}{4} = \frac{4}{16}$.

Now, add the fractions of mushrooms and onions: $\frac{5}{16} + \frac{4}{16} = \frac{9}{16}$.

Subtract this sum from the whole: $\frac{16}{16} - \frac{9}{16} = \frac{7}{16}$.

So, $\frac{7}{16}$ of the pizza is covered with only cheese.

2) Mario starts with $\frac{15}{16}$ of a pizza. He eats $1 \frac{1}{16}$ of a pizza.

Convert $1 \frac{1}{16}$ to an improper fraction: $1 \frac{1}{16} = \frac{17}{16}$.

Now subtract the amount eaten from the amount he had: $\frac{15}{16} - \frac{17}{16} = -\frac{2}{16} = -\frac{1}{8}$.

Since the result is negative, it means Mario ate more than he had. He has $0$ pizza left.

3) Rej has $4 \frac{7}{12}$ pizzas. $\frac{1}{12}$ of them have no toppings.

First, convert $4 \frac{7}{12}$ to an improper fraction: $4 \frac{7}{12} = \frac{55}{12}$.

Now, find the number of pizzas with no toppings: $\frac{1}{12} \times \frac{55}{12} = \frac{55}{144}$.

The number of pizzas with toppings is the total minus the ones with no toppings: $\frac{55}{12} - \frac{55}{144}$.

Convert $\frac{55}{12}$ to 144ths: $\frac{55}{12} = \frac{660}{144}$.

Now subtract: $\frac{660}{144} - \frac{55}{144} = \frac{605}{144}$.

Convert back to a mixed number: $\frac{605}{144} = 4 \frac{29}{144}$.

So, $4 \frac{29}{144}$ of Rej's pizzas have toppings.

4) Elena baked 4 pizzas. She topped $2 \frac{1}{2}$ of them with hot peppers and $\frac{2}{5}$ of them with mushrooms.

First, convert $2 \frac{1}{2}$ to an improper fraction: $2 \frac{1}{2} = \frac{5}{2}$.

Now, add the fractions of pizzas topped with hot peppers and mushrooms: $\frac{5}{2} + \frac{2}{5}$.

Find a common denominator, which is 10: $\frac{5}{2} = \frac{25}{10}$, $\frac{2}{5} = \frac{4}{10}$.

Add: $\frac{25}{10} + \frac{4}{10} = \frac{29}{10}$.

Convert $\frac{29}{10}$ to a mixed number: $2 \frac{9}{10}$.

So, $2 \frac{9}{10}$ of her pizzas were topped with hot peppers or mushrooms.

5) Tucker baked $2 \frac{1}{2}$ pizzas and ordered another $\frac{5}{7}$ of a pizza.

First, convert $2 \frac{1}{2}$ to an improper fraction: $2 \frac{1}{2} = \frac{5}{2}$.

Now, add the pizzas he baked and ordered: $\frac{5}{2} + \frac{5}{7}$.

Find a common denominator, which is 14: $\frac{5}{2} = \frac{35}{14}$, $\frac{5}{7} = \frac{10}{14}$.

Add: $\frac{35}{14} + \frac{10}{14} = \frac{45}{14}$.

Now, he shares $1 \frac{5}{6}$ of his pizza with his friends.

Convert $1 \frac{5}{6}$ to an improper fraction: $1 \frac{5}{6} = \frac{11}{6}$.

Now, subtract the amount shared from the total: $\frac{45}{14} - \frac{11}{6}$.

Find a common denominator, which is 42: $\frac{45}{14} = \frac{135}{42}$, $\frac{11}{6} = \frac{77}{42}$.

Subtract: $\frac{135}{42} - \frac{77}{42} = \frac{58}{42}$.

Simplify $\frac{58}{42}$: divide numerator and denominator by 2: $\frac{29}{21}$.

Convert to a mixed number: $\frac{29}{21} = 1 \frac{8}{21}$.

So, Tucker has $1 \frac{8}{21}$ pizzas left over.