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# Arithmetic patterns and problem solving: FAQ

## What's the difference between a one-step and two-step word problem?

In a one-step word problem, we only need to perform one operation (like addition, subtraction, multiplication, or division) to find the answer. In a two-step word problem, we need to perform two operations

## What is a $2$‍ -step expression?

A $2$-step expression is a math problem that requires two steps to solve. For example, $3x+2x$ is a $2$-step expression. To solve it, we first add $3x$ and $2x$ together to get $5x$, and then we can solve for $x$.

## How do we use estimation in word problems?

In word problems, we can use estimation to help us check our work. For example, if we're trying to find out how many apples there are in $11$ bags, each with $6$ apples, we can estimate that there are about $60$ apples. If we calculate the exact answer and get $15$, we know we've made a mistake.

## What are patterns in arithmetic?

Patterns in arithmetic are sequences of numbers that follow a certain rule. For example, the sequence $2,4,6,8,10$ is a pattern in arithmetic because we're adding $2$ to each number to get the next one.

## How do we use the topics from this lesson in the real world?

There are many ways we use arithmetic and problem solving in the real world! For example, we might use estimation to plan a budget, or we might use two-step word problems to figure out how much we need to save to buy something we want.