Not fully simplifying a surd H
"The Partial Simplify"
The Mistake in Action
Simplify $\sqrt{72}$
Wrong: $\sqrt{72} = \sqrt{4 \times 18} = 2\sqrt{18}$ ✓ Done
Why It Happens
Students find one square factor but don't check if the remaining surd can be simplified further.
The Fix
Always check if your answer can be simplified further!
$\sqrt{72} = \sqrt{4 \times 18} = 2\sqrt{18}$
But $\sqrt{18} = \sqrt{9 \times 2} = 3\sqrt{2}$
So: $\sqrt{72} = 2 \times 3\sqrt{2} = 6\sqrt{2}$
Better method: Find the largest square factor. $72 = 36 \times 2$ $\sqrt{72} = \sqrt{36 \times 2} = 6\sqrt{2}$ ✓
Spot the Mistake
Can you identify where this student went wrong?
$\sqrt{72} = 2\sqrt{18}$
Click on the line that contains the error.
Related Topics
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