Check their diary to see where they’re up to in their reader. Give time for your child to flip through book first. If they are continuing a book, ask them to tell you what’s already happened and let them look at the pictures again for familiarity. Let your child sound out an unknown word, look at pictures and/or read on to cue into what they already know about the story or topic. After 2 guesses tell them the word so the story flow isn’t lost.
Say discouraging things. Do other things if your child is struggling with the reading. (If your child is reading fluently, alternate them reading while you cook one night then reading together at bedtime the next). Compare this child to other siblings etc.
If your child is not understanding what to do, read the instructions carefully. Do a bit each time through the week. Have a tin of sharp lead pencils and an eraser for your child to use. If all else fails, get your child to practice addition, subtraction or multiplication.