Home > Reasoning > Big ideas > Same and different > Imagining missing elements

# Imagining missing elements

Missing elements may be numbers, shapes, variables or other mathematical objects.

They are used to:

• balance or solve equations
• predict terms in number sequences or series and sequences
• complete patterns, tables and arrays
• solve problems.

Mathematical reasoning is needed to describe and identify missing elements.

Missing elements may be used in teaching and assessment. The activity Covered by H is easy to adapt for all year levels.

## Covered by H

This activity focusses on horizontal and vertical place-value patterns in a number grid. A shape is used to cover parts of the grid. Students need to explain what the covered numbers are and how they know.

Foundation Year: Establish understanding of the language and processes of counting by naming numbers in sequences, initially to and from 20, moving from any starting point

Year 1: Develop confidence with number sequences to and from 100 by ones from any starting point. Skip count by twos, fives and tens starting from zero

Year 2: Describe patterns with numbers and identify missing elements

Year 5: Describe, continue and create patterns with fractions, decimals and whole numbers resulting from addition and subtraction

Year 6: Continue and create sequences involving whole numbers, fractions and decimals. Describe the rule used to create the sequence

Year 7: Create algebraic expressions and evaluate them by substituting a given value for each variable

Source