# Array Puzzles

Purpose

This is a level 2 number activity from the Figure It Out series. It relates to Stage 5 of the Number Framework.

Achievement Objectives
NA2-3: Know the basic addition and subtraction facts.
NA2-3: Know the basic addition and subtraction facts.
Student Activity
Specific Learning Outcomes

use addition facts to solve puzzles

Required Resource Materials

FIO, Level 3, Basic Facts, Array Puzzles, page 8

classmate

Activity

#### Activity One

Students enjoy making and completing arrays for both addition and multiplication facts. Students are often given arrays to complete where the addends are provided and they have to find the sum, such as the array in question 1.
Question 2 offers an interesting and challenging alternative because it has missing addends and sums. Students need to recognise that addition and subtraction are inverse operations and to be able to consider the facts in different forms. For example, to find out what number goes in the top right corner of the first array, they need to find the unknown in this equation: 9 +  = 17. Seeing that
addition and subtraction are inverse operations, they can rewrite this as 17 – 9 =  and solve the problem this way.

#### Activity Two

As a variation to this activity, students might like to use this same method and design multiplication arrays for classmates to solve.

Activity One
1. 2. Activity Two