Commonly-made mistakes in word problem

I came across some mistakes while marking the children's homework. I hope that we can highlight these errors so that the children can avoid making them repeatedly.

1. Transfer errors (Pupils fill in the wrong answers especially for questions involving filling in the ovals)
2. No labelling of the unknown (?)

I'm glad the children remember my little tip of identifying the "than" in word problems. They usually involve the drawing of comparison models because we need to compare. The children used paper strips to do an activity today. Note that it is a 2-step word problem but it is not explicitly stated in the question.