Which Coins are Missing?

Freddie is feeling nervous about starting his new job tomorrow as an assistant at the local shop. “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 shop right here, so we can practice.” Zuri made a purchase from Freddie’s van market and the till tells him he needs to give her forty-six pence in change. We can help Freddie get ready for his new job by determining “Which Coins are Missing?” Let’s review the UK coins and their values. We have eight commonly used coins in the UK. These ones have the largest values and are worth one pound and two pounds. "We also have these six coins which are worth smaller amounts." This is a fifty pence coin. This is a twenty pence coin. This is ten pence coin. This is a five pence coin. This is a two pence coin, and this is a one pence coin. 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 pence for Zuri. Zuri shows the following coins and asks him which coins are missing to complete the change. Zuri has shown Freddie two twenty pence coins. 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 would usually start by putting the coins in order from greatest to least value. These two coins are worth the same amount so we put them next to each other like this. Now, let’s add them together. Twenty plus twenty equals forty. Next subtract forty from the total, forty-six. Forty-six minus forty is six. Which coins are missing to make the change? Adding a five pence coin and a one pence coin makes six pence. To make forty-six pence, Freddie would give back two twenty pence coins, a five pence coin, and a one pence coin. Zuri’s next purchase would give the change of sixty-eight pence. She shows Freddie the following coins: a fifty pence, a five pence and a one pence. We need to add the given coin values first before we can find the missing coins. Fifty plus five equals fifty five plus one more equals fifty six. Now, subtract fifty-six from the total. Sixty-eight minus fifty-six is twelve pence. Which two coins are missing? A ten pence coin and a two pence coin would make twelve pence. Freddie would give a fifty pence, a ten pence, a five pence, a two pence and a one pence for change. For the final practice, Freddie needs to make eighty-nine pence, 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 twenty pence, a five pence and a one pence would make eighty-nine. How did we solve? We counted fifty, sixty. Sixty two, sixty three, and subtracted sixty-three from eighty-nine to get twenty-six pence. Freddie would give a fifty pence, a twenty pence, a ten pence, a five pence, a two pence and two one pence coins to make eighty nine pence change. Now that Freddie is ready for his first day at work, let’s summarise. All coins in the UK have a value assigned to them. We can determine missing coins from change given by organising the coins from greatest to least, 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 serve my first customer!” “That’ll be thirteen pounds and sixty-three pence please.”