Welcome to addition and subtraction with parentheses. When we see parentheses in math expressions, we must calculate what's inside them first. This is called the order of operations. The rule is simple: always solve inside parentheses first, then work from left to right. Let's look at an example: ten plus five minus two in parentheses.
Let's work through another example step by step. We have fifteen minus eight plus three in parentheses. Step one: find the parentheses. Step two: calculate inside the parentheses, eight plus three equals eleven. Step three: replace the parentheses with the result, so we have fifteen minus eleven. Step four: calculate the final answer, fifteen minus eleven equals four.
Now let's try a more complex example with multiple operations. We have twenty minus six plus two in parentheses, plus five. When we have multiple operations, we still follow the same rule: parentheses first, then left to right. First, calculate six plus two equals eight. Then substitute to get twenty minus eight plus five. Now work from left to right: twenty minus eight equals twelve. Finally, twelve plus five equals seventeen.
Let's practice with two more examples. Try to solve them in your head first! Problem one: nine minus four in parentheses, plus seven. First calculate nine minus four equals five, then five plus seven equals twelve. Problem two: eighteen minus three plus five in parentheses, minus two. First calculate three plus five equals eight, giving us eighteen minus eight minus two. Then work left to right: eighteen minus eight equals ten, and ten minus two equals eight.
To summarize what we've learned about addition and subtraction with parentheses: Always calculate inside parentheses first, then work from left to right. This is the fundamental order of operations rule. With practice, these problems become much easier to solve.