The complete series of exercise publications I will advise is a perfect helper for every student in the first grade of elementary school.
The titles I can help with mathematics practice all the material discussed in elementary school mathematics lessons.

Mathematics 2nd year - counting by tens, number decomposition, rounding
Mathematics 3rd grade - division, multiplication, written addition and subtraction, Roman numerals, geometry
Mathematics 4th grade - solids, division with remainder, sum of segments, natural numbers
Mathematics 5th grade - associative law, mixed and decimal numbers, fractions or arithmetic mean
The publication is intended for home practice, but teachers will certainly use it as well, e.g. for short papers or substitute lessons. Short exercises fully correspond to the curriculum of primary schools.
The book includes a detailed key to all exercises to check the correctness of your results.