Which Coins are Missing?

Freddie is feeling nervous about starting his new job tomorrow as a cashier at the local market. “What if I mess up tomorrow and go too slow or give people the wrong change!” “You’ll be fine!” “I’ve set up a store right here, so we can practice.” Zuri made a purchase from Freddie’s van market and the register tells him he needs to give her forty-six cents in change. We can help Freddie get ready for his new job by determining... “Which Coins are Missing?” Let’s review the US coins and their values. We have rarely used coins like the one dollar and a half dollar... Quarters have the value of twenty-five cents… dimes are worth ten cents… nickels are worth five cents… and pennies have the value of one cent. When making change, we can use a combination of these coins to make the different amounts. There are many combinations of coins that can be made, but we want to try and make the combination that uses the fewest amount of coins possible. Freddie is thinking of coins that can make forty-six cents for Zuri. Zuri shows the following coins and asks him which coins are missing to complete the change. Zuri has shown Freddie a dime and a quarter. She asks him which two coins are missing. In order to find the missing coins, we need to add up the given coin values and subtract them from the total. We start by putting the coins in order from greatest to least value. Twenty-five and ten more make thirty-five. Which coins are missing to make the change? Adding a dime and penny is the way to make eleven with fewest coins. Zuri’s next purchase would give the change of sixty-six cents. She shows Freddie the following coins… Two quarters and a penny. We need to add the given coin values first before we can find the missing coins. Twenty-five and twenty-five make fifty, and one more make fifty-one cents. Now, subtract fifty-one from the total. Sixty-six minus fifty-one is fifteen cents. Which two coins are missing? A dime and a nickel would make fifteen cents. Freddie would give two quarters, a dime, a nickel, and a penny for change. For final practice, Freddie needs to make eighty-nine cents... and Zuri shows the following coins. Which coins are missing? Pause the video if you need additional time and resume when you're ready. Adding a quarter and a dime are the fewest coins needed to make eighty-nine. How did we solve? We counted twenty-five, fifty, fifty-one. Fifty-two, fifty-three, fifty-four… and subtracted fifty-four from eighty-nine to get thirty-five cents. Freddie would give three quarters, one dime, and four pennies change. Now that Freddie is ready for his first day at work, let’s summarize. All coins in the US have a value assigned to them. We can determine missing coins from change given by… organizing the coins from greatest to least and adding up the known coin values... and subtracting that amount from the total. Then, we find the coin combination needed to make them.... using the fewest coins possible. “I am so excited to ring up my first purchase!” “That’ll be thirteen dollars and sixty-three cents.”