So the diagram also represents $\frac53 \times A = ?$. We can also see the entire rectangle as $\frac53$ of the yellow part, since the yellow part is divided into 3 equal pieces and the entire rectangle is 5 of those pieces. This equation can be re-written as $A \div \frac35 = ?$ because of the relationship between multiplication and division. This is the same as $\frac35 \times ? = A$. And, you can always think of a '+' in front of a number as meaning 'times +1' and a '-' in front of a number as meaning 'times -1'. The yellow part (which represents $A$) is 3 of 5 equal parts of the entire rectangle (whish represents the unknown ?), so A is $\frac35$ of ?. I had never heard of 'keep, change, flip' before But basically, you are just talking about the fact that (-1)(-1) +1 or, more generally, that the product of two negative numbers is negative. Since the entire rectangle is 5, the blue part is $\frac23$ of 5, so this diagram represents $\frac\times 5 = ?$ because you can look at each piece as half of the green part (which is 5), and since there are three pieces, the entire rectangle is $\frac32$ of 5. The blue part of the rectangle (which is ?) represents $\frac23$ of the rectangle because the entire rectangle is partitioned into 3 equal pieces and 2 are shaded. The goal is for students to understand and remember the invert and multiply rule, but at some point they should be able to use it without revisiting these reasons every time. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |