Count one object at a time
Look across the whole collection and give each object one count. The groups and rows change, but every object still counts once.
If you see two full groups of five and three more objects, count the full groups as ten and continue with eleven, twelve, thirteen. Moving an object to another place would not change the total.
Check before you answer
Point or scan in a steady order so that no object is skipped or counted twice.
When a count seems wrong, ask the child to show which objects were counted. The practice questions change the arrangement so the child learns to check the quantity, not memorize one picture.