options: Solve real-world and mathematical problems by writing and solving equations of the form x + p = q and px = q for cases in which p, q and x are all nonnegative rational numbers.

Use variables to represent numbers and write expressions when solving a real-world or mathematical problem; understand that a variable can represent an unknown number, or, depending on the purpose at hand, any number in a specified set.

Write an inequality of the form x > c or x < c to represent a constraint or condition in a real-world or mathematical problem. Recognize that inequalities of the form x > c or x < c have infinitely many solutions; represent solutions of such inequalities on number line diagrams.

Understand solving an equation or inequality as a process of answering a question: which values from a specified set, if any, make the equation or inequality true? Use substitution to determine whether a given number in a specified set makes an equation or inequality true.
problem_activity: Task
Decide which of the following equations best represents each situation.
| $$x + 2= 10$$ | $$x=10+2$$ | $$2\cdot10=x$$ |
|---------------|------------|----------------|
|  $$x+10=2$$   | $$10x=2$$  |   $$2x=10$$    |
After Lou poured 2 liters of water into a large jug, the jug contained 10 liters of water. How many liters were in the jug to start?
Clara ran 10 miles, which was twice as far as Nina ran. How far did Nina run?


correct_option_index: 0

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