The expression equivalent to -21.8 - (-18.3) would be option A; -21.8+18.3.
What are equivalent expressions?
Those expressions that might look different but their simplified forms are the same expressions are called equivalent expressions.
To derive equivalent expressions of some expression, we can either make it look more complex or simple.
The given expression is
-21.8 - (-18.3)
So, open the bracket and distribute the negative;
-21.8 (+18.3)
Thus, the expression equivalent to -21.8 - (-18.3) would be option A; -21.8+18.3.
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