Answer
The statement is false.
$$(7 \times 10^{5}) + (2 \times 10^{-3})=7.00000002\times 10^{5}$$
Work Step by Step
$$(7 \times 10^{5}) + (2 \times 10^{-3}) = 9 \times 10^{2}$$
To add scientific notations with different exponents, the exponent of 10 is the smaller expression must be adjusted such that it matches that of the larger expression.
In this case, the smaller exponent is $-3$ while the larger exponent is $5$.
Determine the number by which to increase the smaller exponent by so it is equal to the larger exponent.
Thus,
$$5-(-3) = 8$$
Increase the smaller exponent by this number and move the decimal point of the number with the smaller exponent to the left the same number of places.
Thus,
$$2 \times 10^{-3} = 0.00000002\times 10^{5}$$
Rewrite the whole expression:
$$7 \times 10^{5} +0.00000002\times 10^{5}$$ $$=7.00000002\times 10^{5}$$
