Why do they have a temper tantrum?
A tantrum usually results from the child’s frustration at not getting what they want, or not being understood because they can’t express themselves well enough yet. It’s easier to accept if you understand that it’s purely a display of frustration. They’re trying to learn how to do it themselves, they’re not deliberately being naughty. Tantrums are a normal part of being a toddler. Toddlers are developing their independence and trying to gain control over what they do. “No-me do!” is a common statement.
If you can see their frustration building, try to distract them with another activity.