Please help quickly! I would rlly appreciate it :)

Estimate the product. round the first factor to the nearest whole number, round the second factor to the nearest ten, and then multiply. 3 8/9 × 96

Jada has a meal in a restaurant she adds up the prices listed on the menu for everything they ordered and gets a subtotal of $42.00. when the check comes, it says they also need to pay $3.99 in sales tax. what percentage of the subtotal is the sales tax

Wrote and expression for the difference of p and 4