Using Bar Models To Solve Complex Addition And Subtraction Word Problems

Hi, my name is Ben. And in this video we're going to look at solving complex multi step word problems using the bar model. Here is the question. A wizard has 93,320 dragon eggs. In a cave, a magician has 219 eggs less than the wizard. A witch has 320 more eggs than the wizard. How many dragon eggs did I have altogether? So we're dealing with larger numbers, which is fine, but the children have to be able to see this problem in order to solve it. Okay, let's use the bar model. Here's the wizard with his 93,320 eggs. And then we have the magician who has got less eggs and therefore the bar will be smaller. Now as the magician has 219 eggs less than the wizard, the inverse is that the wizard will have 219 more. So we can do 93,320 minus 219 and the children can use a number line for that, or they can use column subtraction, but they will get the answer 93101. The next step is the witch. She will have the largest bar because she has 320 more eggs than the wizard. So to find out how many eggs the witch has got, we need to do 93,320. Add 320, which gives us 93,640. The final part of this question is to go back how many dragon eggs altogether? So we need to look at the three, the three figures. 93,320, 93,101 and 93,640. And again, column addition would work there to add them all together to get the answer of 280,061. And that's how you can use the bar model to solve problems that are a lot more complex and multi step.