Following is the stockholders' equity section of the Merck & Co., Inc., balance sheet.

Merck & Co., Inc. Stockholders' Equity ($ millions)	Dec. 31, Current Year	Dec. 31, Prior Year
Common stock, $0.50 par value
Authorized- 6,500,000,000 shares
Issued- 3,312,587,054 shares in current and prior year	$1,657	$1,657
Other paid-in capital	36,987	37,298
Retained earnings	46,021	39,257
Accumulated other comprehensive loss	(4,323)	(2,197)
	80,342	76,015
Less treasury stock, at cost:
737,005,489 shares in current year and 649,576,808 shares in prior year	32,114	28,789
Total Merck & Co., Inc. stockholders' equity	$48,228	$47,226

a. Explain the derivation of the $1,657 million in the common stock account. Complete the calculation of total amount of shares.

Enter share amounts in millions ($3,000,000 = $3).

Round share amounts to the nearest whole number.

b. Using December 31, current year balances, at what average issue price were the Merck common shares issued?

Round answer to two decimal places.

c. At what average cost was the Merck treasury stock as of December 31 of the current year?

Round answer to two decimal places.

d. How many common shares are outstanding as of December 31 of the current year?

Enter full number - do not convert to millions or round answer.