Baby School (easy question)

Notice to Brilliant:

Don't let users post so simple questions on the name of algebra for the sake of other users. By the way the answer is 9.

$1 + 2 = (1·2)·1 = 2$

$2 + 3 = (2·3)·2 = 12$

$3 + 4 = (3·4)·3 = 36$

$4 + 5 = (4·5)·4 = 80$ ..........[proved]

What are the 6% doing?

4+5=9

This is a basic addition for kids.

4 + 5 = 9

4+5= 9 , Btw Seriously do you need a solution?

$4 + 5 = \color{#69047E}{\boxed{9}}$ .

1+1+1+1+1+1+1+1+1=9 It's simple.. :)

o o o o + o o o o o = o o o o o o o o o

9

9

4 + 5 = 9

Simple.