Inattention and hyperactivity/impulsivity are the key behaviors of ADHD. Some people with ADHD only have problems with one of the behaviors, while others have both inattention and hyperactivity-impulsivity. Most children have the combined type of ADHD.

People with symptoms of inattention may often:

• Overlook or miss details, make careless mistakes in schoolwork, at work, or during other activities
• Have problems sustaining attention in tasks or play, including conversations, lectures, or lengthy reading
• Not seem to listen when spoken to directly
• Not follow through on instructions and fail to finish schoolwork, chores, or duties in the workplace or start tasks but quickly lose focus and get easily sidetracked
• Have problems organizing tasks and activities, such as what to do in sequence, keeping materials and belongings in order, having messy work and poor time management, and failing to meet deadlines
• Avoid or dislike tasks that require sustained mental effort, such as schoolwork or homework, or for teens and older adults, preparing reports, completing forms, or reviewing lengthy papers
• Lose things necessary for tasks or activities, such as school supplies, pencils, books, tools, wallets, keys, paperwork, eyeglasses, and cell phones
• Be easily distracted by unrelated thoughts or stimuli
• Be forgetful in daily activities, such as chores, errands, returning calls, and keeping appointments

People with symptoms of hyperactivity-impulsivity may often:

• Fidget and squirm in their seats
• Leave their seats in situations when staying seated is expected, such as in the classroom or the office
• Run or dash around or climb in situations where it is inappropriate or, in teens and adults, often feel restless
• Be unable to play or engage in hobbies quietly
• Be constantly in motion or “on the go,” or act as if “driven by a motor”
• Talk nonstop
• Blurt out an answer before a question has been completed, finish other people’s sentences, or speak without waiting for a turn in a conversation
• Have trouble waiting for his or her turn
• Interrupt or intrude on others, for example in conversations, games, or activities

https://www.nimh.nih.gov/health/topics/attention-deficit-hyperactivity-disorder-adhd/index.shtml