Pupils' learning abacus mental arithmetic has many benefits to improve their mathematical thinking ability. First of all, abacus mental arithmetic is a method of calculation through abacus, which can train students' hand-eye coordination and concentration. These abilities are very important for students' mathematics study, because they can help students better understand and master mathematics knowledge.

Secondly, abacus mental arithmetic can cultivate students' logical thinking ability. In mental abacus calculation, students need to operate according to certain rules and steps, which requires them to have strong logical thinking ability. By practicing abacus mental arithmetic for a long time, students can gradually cultivate a rigorous and meticulous way of thinking, which is very helpful for them to solve problems in mathematics learning.

In addition, abacus mental arithmetic can also improve students' memory. In abacus mental arithmetic, students need to remember some numbers and operation rules, which puts higher demands on their memory ability. By practicing abacus mental arithmetic for a long time, students can gradually improve their memory, which is also of great help to them in other subjects.

In a word, primary school students' learning abacus mental arithmetic has many benefits to improve their mathematical thinking ability. It can train students' hand-eye coordination, concentration, logical thinking and memory, and lay a solid foundation for them in mathematics learning. Therefore, parents and teachers should encourage their children to learn abacus mental arithmetic and help them develop their mathematical thinking ability better.