The results of total testing from the years 2015-2022 on the mathematical and verbal achievement of Lithuanian pupils (N [approximately equal to] 250,000) are presented. These are the standardised tests from grades 4 to 12. The K-Means method has discovered six types of achievement. The highest achievement type is dominated by girls (61.1%) who perform well on both mathematical and verbal tasks. The lowest achievement type is dominated by boys (57.4%) who solve both mathematical and verbal tasks extremely poorly. Each of these types makes up 1/5 of the population, and the gap between the means of their groups is about 2.5 standard deviations. The remaining four types of achievement are in the 20th to 80th percentile and make up about 60% of the population. Differences in means within the same type between mathematic and verbal achievement average 0.85 standard deviations or span one quartile. Gender differences are clearly visible in this subgroup: boys solve mathematical tasks better and verbal tasks worse; girls solve verbal tasks better and mathematical tasks worse. Big data may form a mixed distribution. It is appropriate to first discover the basic types of achievement and only then look for gender-specific differences. Such a type-building approach is heuristically superior to the conventional approach of working only with the mixed dataset.