Frustration in kids can be caused by:

• Inability to get what they want
• Being asked to do something they don't want to do
• Physical needs such as hunger or tiredness
• Changes in routines or life situations
• Interruption of something they enjoy
• Developmental leaps where they cannot quite master the next stage
• Mental health conditions such as ADHD, autism, obsessive-compulsive disorder, and Tourette’s syndrome.
• Other.

Video to help students manage their frustrations:

Coping Skills For Kids - Managing Feelings & Emotions For Elementary-Middle School | Self-Regulation - YouTube