The rapid development of science and technology these days is changing attitudes towards mathematics. Mathematics is perceived as a significant part of world science, technology, and human culture. It is an important abstract deductive and inductive, empirical - experiential, experimental cognition instrument. The subject of mathematics has a huge significance in developing students' ability to calculate, think logically and formalize, developing their visual, spatial, and probabilistic thinking, analytical and synthetic comprehension, and cognition skills. Understanding and applying well-known mathematical concepts, models, methods, connections to analyse various situations helps each student not only to perceive the world but also to adopt the culture of human thinking and activity that has developed over the centuries. IT technologies allow investigating the behaviour of students in the process of learning mathematics online. With the help of technology, it is possible to track every mouse click in e-environment and analyse how students behave during the test. Having this data, it is possible to investigate the behaviour of different groups of students during the test: boys and girls, gifted and having difficulties in the learning process students. Besides, it is possible to analyse how students understand the information in different learning styles: verbal, kinaesthetic. The article presents the analysis of the study, which was investigating the attitude of the 3rd-grade students and their teachers towards online tests. The article contains the description of 3rd-grade students’ diagnostic test, students’ achievements, and behavioural peculiarities during the mathematical test. The research was conducted among 3rd-grade students in Latvian schools. (This year online diagnostic tests were completed by 1705 students from 57 schools).