Asher has 13 post-it notes more than Gillian. How many post-it notes must Gillian get from Asher so that she has 29 post-it notes more than him?

	Asher	Gillian
Comparing Asher and Gillian at first	13 more
Before
Change	- ?	+ ?
After
Comparing Asher and Gillian in the end		29 more

If Asher gives 13 post-it notes to Gillian, she will have 13 more post-it notes than him. However, Gillian must have 29 more post-it notes than Asher in the end. So, Asher has to give Gillian more post-it notes.

Number of more post-it notes that Asher has to give to Gillian
= (29 - 13) ÷ 2
= 16 ÷ 2
= 8

So after giving 13 post-it notes to Gillian, Asher has to give her another 8 more post-it notes so that she has 29 post-it notes more than him.

Total number of post-it notes that Gillian needs to get from Asher
= 13 + 8
= 21

Answer(s): 21