have (got) (someone's) number

to understand the way someone behaves.

They've got our number – they play harder against us than anybody else.

She seems to know exactly what people our age want – she definitely has our number.

• knock off their perch
• knock on the head
• knock on wood
• knock out
• knock sense into
• knock sense into someone
• knock sideways
• knock socks off
• knock someone dead
• knock someone for a loop
• knock someone for six
• knock someone into shape
• knock someone off feet
• knock someone off pedestal
• knock someone off perch
• knock someone off their feet
• knock someone off their pedestal
• knock someone off their perch
• knock someone out
• knock someone's block off
• knock someone sideways
• knock someone's socks off
• knock someone up
• knock some sense into
• knock some sense into someone