She gives the boy she likes 10 stickers.
After giving the boy his stickers, she has 100 – 10 = <<100-10=90>>90 stickers left.
She gives her best friends 90 / 2 = <<90/2=45>>45 stickers
This leaves Clara with 90 – 45 stickers = <<90-45=45>>45 stickers.
#### 45