Todrick Company is a merchandiser that reported the following information based on $1,000$ units sold:

Sales $ $420,000$

Beginning merchandise inventory $ $28,000$

Purchases $ $280,000$

Ending merchandise inventory $ $14,000$

Fixed selling expense $?$

Fixed administrative expense $ $16,800$

Variable selling expense $ $21,000$

Variable administrative expense $?$

Contribution margin $ $84,000$

Net operating income $ $25,200$

Required:

$1.$ Prepare a contribution format income statement.

$2.$ Prepare a traditional format income statement.

$3.$ Calculate the selling price per unit.

$4.$ Calculate the variable cost per unit.

$5.$ Calculate the contribution margin per unit.

$6.$ Which income statement format $($traditional format or contribution format$)$ would be more useful to managers in estimating how net operating income will change in response to changes in unit sales?