Arithmetic asks the person to solve mostly spoken problems mentally
In the WAIS Arithmetic subtest, the person works on quantitative problems presented primarily aloud and must retain the relevant information while calculating an answer mentally. In WAIS-IV, Arithmetic is a core subtest of the Working Memory Index, or WMI, together with Digit Span.
In WAIS-5, Arithmetic moves to a secondary fluid-reasoning role. It is not part of primary WMI or FSIQ, but contributes to the Quantitative Reasoning Index and Expanded Fluid Index. WAIS-IV and WAIS-5 compared explains the wider change.
The person cannot begin by writing out an equation. They must remember the conditions, decide what calculation is needed, and retain intermediate results while working mentally. Holding information and reasoning with it at the same time is a defining feature of the task.
Outside the assessment, writing down the conditions and intermediate results separates the retention demand from the calculation demand.
What higher and lower Arithmetic scores can show
A higher scaled score indicates strength in retaining spoken quantitative conditions, identifying their relationship, choosing an operation, and completing the mental calculation within the time limit. The score is not determined by working memory (Gwm) alone: quantitative reasoning, arithmetic knowledge, attention, and accuracy also contribute.
When the score is lower, behaviour during the task can help identify the stage at which demand increased:
- numbers or conditions from the first part of the problem are lost while the remainder is being heard;
- the numbers are retained, but the quantitative relationship or required operation is difficult to identify;
- the method is understood, but an intermediate result is difficult to retain during mental calculation; or
- the solution can be reached, but not within the time limit.
Interpret Arithmetic alongside the wider index profile and behaviour during testing; the full WAIS result-reading guide explains how the pieces fit together.
How Arithmetic differs from Digit Span, Letter-Number Sequencing, and Figure Weights
| Subtest | Main material | How it differs from Arithmetic |
|---|---|---|
| Digit Span | Numbers | Reproduce numbers in the original, reverse, or ascending order without a verbal quantitative relationship or calculation |
| Arithmetic | Problems involving quantitative relationships | Retain the conditions, choose an operation, and calculate mentally |
| Letter-Number Sequencing | Numbers and letters | Separate two types of information and arrange each in a specified order without calculation |
| Figure Weights | Balanced scales and figures | Derive quantitative equivalence from visual conditions rather than retaining and calculating from a spoken problem |
Among WAIS-IV WMI subtests, Arithmetic shows the strongest direct influence of quantitative reasoning and calculation.
BrainTypeIQ Computation Span separates calculation and later recall
BrainTypeIQ Computation Span also combines processing with retention, but the person calculates answers and retains intermediate results for later recall rather than solving one spoken quantitative problem. This gives BrainTypeIQ a distinct view of calculation under working-memory demand.