{ [ 2 × (3 + 4) ] − 5 } + 6
When you see brackets inside braces, don't panic — the trick is simple: solve from the inside OUT.
Here's our expression. We need to find what it equals.
Start with the innermost grouping. The parentheses are deepest inside, so we solve those first.
Three plus four is seven. We rewrite, replacing the parentheses with seven.
Look — the brackets are now innermost. Let's solve those next.
Two times seven is fourteen. Rewrite once more.
Just the braces are left to handle.
Fourteen minus five is nine.
Now the simple part: nine plus six is fifteen.
We got fifteen! Remember: with nested groupings, always work from the inside out.