As Lpfö 98 says, preschool has got a commission to giver every child some comprehension of mathematics and fundamental properties in the concepts of number, measurement and design. The purpose of this study has been to describe the opinions and attitudes of preschool teachers towards mathematics in preschool, and to tell how they describe their work with mathematics in the preschool activities. The purpose has also been to observe how they pay attention to mathematics during the day in preschool and compare that to their own descriptions. To find out about this, I observed and interviewed three different preschool teachers. The result shows that they know very well how their preschool activity works. The preschool teacher, who thinks that mathematics is not very important in preschool, doesn’t pay attention to mathematics in a conscious way in her work with the children. But the mathematics is always present, mostly when she talks with the children unconsciously using mathematical concepts. In the same way the concepts are a part of the day for the preschool teacher who “sometimes tries to think about mathematics”. The concepts are used in conversations with the children, but there are no conscious strategies of how to use mathematics during the day in the work with the children in preschool. The third preschool teacher describes how she tries to make the mathematics clear for the children. The observation also shows that she sees the mathematics around the children and use it in a conscious way, in the activities in preschool. My conclusion is that preschool teachers describe their work with mathematics in preschool in the same way as they really do the mathematical work. Keywords. Preschool, preschool teacher, mathematical activities, mathematics.