You can download the popular educational aid (3000 примеров по математике: 2 класс) by O.V. Uzorova and E.A. Nefedova for free through several online resources. This series is specifically designed to help students master basic arithmetic and reach "automaticity" in their counting skills. Where to Download (Free PDF/Online) Direct PDF Links:

Aims for a solving speed of 4-7 seconds per example to prove the student has fully mastered the topic.

Includes space at the bottom of each column to record time, with "ideal" and "satisfactory" benchmarks to track progress.

O.V. Uzorova & E.A. Nefedova (Couting to 100) — Direct link to the full manual focusing on counting within 100.

Community pages like Primary School | VPR Prep and I am a Primary Teacher host various versions, including Part 1 and Part 2, as PDF files.