Related Experiment Video
Updated: Aug 11, 2026

Multimedia Battery for Assessment of Cognitive and Basic Skills in Mathematics (BM-PROMA)
Published on: August 28, 2021
What do semi-illiterate adults know about 2-digit Arabic numbers?
Guilherme Wood1, Hans C Nuerk, Patrícia Freitas
1Department of Neurology, Section Neuropsychology, University Hospital RWTH-Aachen, Aachen, Germany. gwood@ukaachen.de
Abstract:
Brazilian semi-illiterates (n=19) with 1 to 4 years of academic training compared 2-digit Arabic numbers. Like competent readers, semi-illiterates responded faster and more accurately when the larger number also had the larger unit digit (unit-decade compatibility). Even semi-illiterates with minimal academic training were sensitive to the unit-decade compatibility on number comparison. Probably semi-illiterates derive their ability to automatically activate unit-decade segmentation directly from the oral/verbal number representation. Interestingly, processing speed had an effect on two-digit number comparison. Faster participants showed a smaller or even inverted unit-decade compatibility. Processing speed reflects increased automatization of number segmentation and better selection of the decade-digits for comparison, what eliminates the semantic interference of units. In line with previous research, our data suggest that unit-decade segmentation plays a pervasive role in Arabic number comparison.
Related Concept Videos
Uncertainty in Measurement: Reading Instruments
Numerical Calculations
The solution to a problem is obtained using different methods. While manually solving algebraic symbols is one of the most common methods, the graphical method is often preferred. Computers...
Real Number Operations
Rules for Significant Figures
It should be emphasized that when we represent measured values, the...
Significant Figures in Calculations
Complex Numbers

