Answer:
-4.2
Step-by-step explanation:
Taking the expression at face value, it is ...
42/-10 = -42/10 = -4.2
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Comment on "standard form"
In the US, a number is in standard form if it is written as a sequence of decimal digits and a decimal point (if there is a fractional part), usually with no leading zeros (left of the decimal point). The sign is prepended to that digit string, as shown above.
In the UK, a number is in standard form if it is written in "scientific notation." The rule for writing a number in standard form is that first you write down a number between 1 and 10, then you write ×10(to the power of an integer). Usually powers of 0, or multipliers of 1, are not written. Then the number here is still -4.2, rather than -4.2×10⁰.
