MoCA Calculation Skills 2 — Questions and Answers
Question 1: Which MoCA task most directly evaluates calculation and numerical reasoning skills?
- Clock drawing
- Trail-making task
- Serial 7 subtraction (Correct answer)
- Letter fluency
Correct answer: Serial 7 subtraction
The serial 7 subtraction task (100, 93, 86, 79, 72, 65) is the primary arithmetic task in the MoCA and is the standard measure of calculation under the attention/concentration domain.
Question 2: How is the MoCA serial 7 task scored when a patient gives the sequence 93, 87, 80, 73, 66?
- 0 points — the sequence is wrong
- 1 point
- 2 points
- 3 points (Correct answer)
Correct answer: 3 points
Each subtraction is scored independently from the prior answer. 93 is correct (100-7=93); 87 is incorrect (93-7=86); 80 is correct (87-7=80); 73 is correct (80-7=73); 66 is correct (73-7=66). That is 4 correct = 3 points.
Question 3: A patient who scores 0 on serial 7s but performs well on all other MoCA domains likely has difficulty with:
- Severe global dementia
- Selective arithmetic or sustained concentration difficulty (Correct answer)
- Language dysfunction
- Memory consolidation failure
Correct answer: Selective arithmetic or sustained concentration difficulty
Zero on serial 7s in isolation may indicate selective arithmetic difficulty, high test anxiety, or limited education rather than global cognitive impairment, especially when other domains are intact.
Question 4: What is the maximum score possible for the serial 7 subtraction task?
- 1 point
- 2 points
- 3 points (Correct answer)
- 5 points
Correct answer: 3 points
Serial 7s is scored out of 3 points: 4-5 correct subtractions = 3 pts, 2-3 correct = 2 pts, 1 correct = 1 pt, 0 correct = 0 pts.
Question 5: Why is serial 7 subtraction considered a measure of cognitive functioning beyond simple arithmetic?
- Because it is timed
- Because it tests vocabulary
- Because it requires working memory and sustained mental effort (Correct answer)
- Because it involves visual-spatial processing
Correct answer: Because it requires working memory and sustained mental effort
Serial 7 subtraction requires holding the previous answer in working memory while performing a calculation, taxing attention, concentration, and working memory simultaneously — not just arithmetic ability.
Question 6: If a patient cannot complete the serial 7 task due to a math learning disability disclosed before testing, the examiner should:
- Skip the task entirely and award 3 points
- Skip the task and award 0 points
- Administer the task and document the pre-existing condition when interpreting results (Correct answer)
- Replace it with a different arithmetic task
Correct answer: Administer the task and document the pre-existing condition when interpreting results
Noted pre-existing conditions affecting serial 7 performance should be documented in clinical notes. The score is still recorded as earned, and the context informs clinical interpretation.
MoCA Calculation Skills 2
Which MoCA task most directly evaluates calculation and numerical reasoning skills?