Question

1. use mental math to find the missing number. 9.2 + n + 2.5 = 15.8

3.7 problem solving: money
learning target: solve multi - step word problems involving money.

1. newton buys a board game for $9.99 and a pack of trading cards for $2.99. he gives the cashier a $20 bill. how much change does he receive?
2. descartes has $378.97 in his bank account. he withdraws $59.50 one day and then deposits $20.44 the next day. how much money is in his bank account now?
3. a bowling alley charges $7.50 for each person to bowl and $2.25 to rent a pair of shoes. how much does it cost you and your friend to bowl and rent shoes?
4. your uncle wants to buy a monthly garage parking pass that costs $49.75. he has five $10 bills, one $5 bill, five $1 bills, and 3 quarters. use the table to show three different ways your uncle could pay for the pass and the change that he receives.

$10 bills $5 bills $1 bills quarters amount given to cashier change received

Explanation:

Step1: Combine known numbers

$9.2 + 2.5=11.7$

Step2: Solve for $n$

$n = 15.8-11.7$
$n = 4.1$

Step3: Solve problem 27

Find total cost: $9.99 + 2.99=12.98$
Change = Amount given - Total cost
Change = $20 - 12.98 = 7.02$

Step4: Solve problem 28

First, subtract withdrawal: $378.97-59.50 = 319.47$
Then, add deposit: $319.47+20.44 = 339.91$

Step5: Solve problem 29

Cost for one - person: $7.50+2.25 = 9.75$
Cost for two - people: $9.75\times2=19.50$

Step6: Solve problem 30

Total money uncle has: $5\times10 + 5\times1+1\times5+3\times0.25=50 + 5+5 + 0.75=60.75$
Way 1:

• Use 4 $10$ - bills, 1 $5$ - bill, 4 $1$ - bills, 3 quarters
• Amount given: $4\times10+1\times5 + 4\times1+3\times0.25=40 + 5+4 + 0.75=49.75$
• Change: $49.75-49.75 = 0$

Way 2:

• Use 5 $10$ - bills
• Amount given: $5\times10=50$
• Change: $50 - 49.75=0.25$

Way 3:

• Use 4 $10$ - bills, 1 $5$ - bill, 5 $1$ - bills
• Amount given: $4\times10+1\times5+5\times1=40 + 5+5=50$
• Change: $50 - 49.75 = 0.25$

Answer:

$n = 4.1$
Newton's change: $\$7.02$
Descartes' account balance: $\$339.91$
Cost for you and your friend: $\$19.50$
Way 1: 4 $10$ - bills, 1 $5$ - bill, 4 $1$ - bills, 3 quarters; Amount given: $\$49.75$; Change: $\$0$
Way 2: 5 $10$ - bills; Amount given: $\$50$; Change: $\$0.25$
Way 3: 4 $10$ - bills, 1 $5$ - bill, 5 $1$ - bills; Amount given: $\$50$; Change: $\$0.25$