Answer
The heart beats $2.94336 \times 10^{9}$ times over a lifetime of $80$ years.
Work Step by Step
$$\frac{70 times}{minute} \times \frac{60minute}{1hour} \times \frac{24hours}{1day} \times \frac{365days}{1year} \times 80years$$ $$= 2,943,360,000 times$$
Expressed in scientific notation as $2.94336 \times 10^{9}$ times.
