# Question Video: Reading Data from a Double Bar Graph Involving Subtraction

The graph shows the number of visitors to three museums in 2005 and 2006. Calculate the difference in number of visitors the National museum had between the two years.

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### Video Transcript

The graph shows the number of visitors to three museums in 2005 and 2006. Calculate the difference in number of visitors the National Museum had between the two years.

This graph shows three different museums’ visitor numbers, but we are only interested in the National Museums. So we know that we can focus on these two lines. We’re looking for the difference between the two years, and that means we’ll need to subtract.

The red line represents 2006, and the green Line represents 2005. This key at the bottom of our graph tells us that the green would be 2005 and the red would be 2006. 2006 had 200 visitors at the National Museum, and 2005 had 100 visitors to the National Museum.

And what would be the difference between these two years? To find the difference, we’ll take the number of visitors in 2005 and subtract that from the number of visitors in 2006. 200 minus 100 equals 100. The difference in number of visitors at the National Museum between 2005 and 2006 was 100 visitors.