Arithmetic requires mostly spoken problems to be solved 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 the Japanese WAIS-IV, Arithmetic is a core subtest of the Working Memory Index, or WMI, together with Digit Span.
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.
Arithmetic combines retention, quantitative reasoning, and mental calculation under time limits
The task requires a continuous sequence of processes:
- listen to the numbers and conditions in the problem;
- retain the necessary information briefly;
- identify the quantitative relationships;
- choose the required operation, such as addition, subtraction, multiplication, or division;
- calculate while retaining intermediate results; and
- answer within the time limit.
The Arithmetic score is not determined by working memory, or Gwm alone. Quantitative reasoning, basic arithmetic knowledge, accuracy of mental calculation, attention, and performance under the time limit all contribute. Arithmetic can therefore show a different pattern of strengths and demands from Digit Span even though both belong to WMI in the Japanese WAIS-IV.
What higher and lower Arithmetic scores can show
In the Japanese WAIS-IV, a higher scaled score indicates that, compared with people of the same age, the person was strong at retaining spoken quantitative conditions, identifying their relationship, and completing the necessary mental calculation within the time limit. The task involves not only calculation speed but also understanding the problem and translating it into an operation.
When the score is lower, behavior 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.
Math anxiety can also affect Arithmetic performance. One study found that math anxiety predicted WAIS-IV Arithmetic scores but did not show the same relationship with Digit Span or Letter-Number Sequencing, suggesting that task-specific tension can also be useful to consider. Arithmetic should be read with WMI, other subtests, and the observations recorded during testing, following the full WAIS result-reading sequence.
Everyday tasks with related demands include estimating a cost or duration from spoken information and deriving a required quantity from several numerical conditions. Writing down the conditions and intermediate results reduces the retention demand that arises before the arithmetic itself.
How Arithmetic differs from Digit Span and Letter-Number Sequencing
| 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 |
Among the Japanese WAIS-IV WMI subtests, Arithmetic shows the strongest direct influence of quantitative reasoning and calculation. BrainTypeIQ Computation Span also combines processing with retention, but its purpose and format differ: the person calculates answers and retains intermediate results for later recall rather than solving one spoken quantitative problem. Its items, online administration, timing, scoring, and norms are separate from WAIS, and the task gives BrainTypeIQ a distinct calculation-and-memory measure within its working-memory domain.
Arithmetic is a secondary fluid-reasoning subtest in the 2024 US WAIS-5
Arithmetic remains in the 2024 US WAIS-5, but it moved from the standard WMI structure to a secondary subtest in the fluid-reasoning domain. It is not part of the standard WMI and is not one of the seven subtests used to calculate FSIQ.
In the US edition, Arithmetic contributes to the Quantitative Reasoning Index and the Expanded Fluid Index. Its role has therefore changed from a core working-memory subtest in the Japanese WAIS-IV to a secondary subtest that adds information about quantitative and fluid reasoning in the US WAIS-5.
WAIS-IV and WAIS-5 compared explains the wider changes in index and FSIQ composition.