Limited recall of addition and subtraction basic facts

Diagnostic questions

  1. Tell the student that you are filling boxes of eggs. The boxes are similar to tens frames. Show the student an empty tens frame and ask the following questions:
    a. If I have already put seven eggs in the box, how many eggs do I need to fill the box?
    b. If I give you a full box and you take out four eggs, how many eggs are left in the box?
  2. Tell the student that you have a machine that doubles numbers. If you put in a 2, out comes a 4!
    What will the machine produce if you put in the number:
    a. 3?
    b. 5?
    c. 8?
    d. 10?

What to notice in the student’s response

Does the student have fast, fluent recall of their basic facts for:

  • addition and subtraction facts to 10?
  • doubling to 20?

Observe whether the student uses another method to solve each problem, for example, counting on their fingers.

Deliberate acts of teaching

Materials

Identifying patterns and relationships is a key component of mathematical thinking. When learning a new basic facts set, the emphasis should be on making connections between different facts.

+/– Flashcards
Have the student explore the relationships between the three numbers on each card by writing out families of addition and subtraction equations. For example, for 3, 9, 6, the student could write and read aloud 3 + 6 = 9, 6 + 3 = 9, 9 – 6 = 3, and 9 – 3 = 6. Cover up one of the numbers and ask the student to work out what the hidden number is. Have them practise with a small number of cards until they can work out the answers without reverting to counting, gradually adding cards as the student recalls each fact more easily.

Memory Doubles
Give the student practice at naming the doubles facts to 20, starting with doubles to 10. Play the Memory Doubles game (www.nzmaths.co.nz) with the student.

What to do next if the student is stuck

Help the student to develop part–whole thinking by using counters and coloured pens. Ask the student to make a group of eight using counters, starting with one blue counter and seven red counters. Write the equation using blue, red, and black pens. Ask the student to make eight using two blue counters, and then three blue counters, continuing until there are eight blue counters and no red counters. Give the student another number to work with and ask them to write as many equations as they can, using the counters as a guide.
Give the student practice with doubles to 10, encouraging them to use their fingers as a visual aid.

Initiating home-based activities

Number Boggle
Print out the Number Boggle game (www.nzmaths.co.nz). Ask the student to use it to find at least five equations and to write them out in full.
Number Facts Activities for Advanced Counting Children (www.nzmaths.co.nz) provides suggestions of activities that can be played at home.

Next teaching steps back in the classroom

Continue working on the transition from advanced counting to early additive, using the learning experiences described in Book 5: Teaching Addition, Subtraction, and Place Value.