Idea 5of 23Builds onWords into an expression
A picture into an expression
How do you write a picture as an expression?
Today you'll discover
- which part of the picture is 3n
- which part is + 2
- how the words say the same thing
Think firstThree bags of n marbles, and 2 loose
Which expression shows all the marbles?
Decide first, then press Next. Match each part of the picture to a part of the expression.
Three bags marked n and 2 loose squares. Then labels under them, 3 bags: 3n and 2 loose: plus 2, the expression 3n + 2, and the words 3 times a number, plus 2. The last step shows four boxes of n beads and 1 loose bead.
See the whole ideathe big idea and the key word, in one place
The big idea
Count the groups of n for the number in front, then add the loose ones on.
For example4 packs of n cards and 6 loose cards: 4n + 6. 2 bags of n with 1 taken out: 2n − 1.
Easy to get wrongLoose ones are never multiplied. Only the groups of n are.
Key word
- algebraic expression
- numbers, letters and signs that show a value, like 3n + 2
Ready to use it?
- Write an expression for a picture.
- Draw a picture for an expression.