I selected the correct geometric fact, theorem, formula or transformation and used a clear diagram with appropriate labels and units.
Even Better If (EBI)
I will name the fact or theorem, show the substitution or construction step and check whether the size, direction and units of the result are reasonable.
Stretch and deep challenge
Stretch: If a=(4,−1) and b=(−2,5), find 3a+2b.
Deep challenge: Prove vector AB+BC=AC for A=(1,1),B=(4,3),C=(7,−2).