The main models of DNA computing are self-assembly of DNA and RDNA. Disadvantages of these models are low speed perform arithmetic operations, the high probability of errors of computing, and perform the calculation with only fixed-point numbers. In article is represented method of encoding numbers by DNA strands. Numbers can be encoded by any base initially. This method does not require to translate the number into a binary number system. Each number is encoded by digit with the DNA. As compared with known methods, the proposed method uses a shorter length of DNA strands. The proposed method can increase speed encoding of numbers, improve the accuracy of the calculations and to reduce errors in the formation of the encoded data. In article is represented also the operations to perform arithmetic operations. The use of the proposed method of encoding numbers and proposed operations over DNA allows to increase speed of computation, and perform calculations not only with fixed-point numbers and floating-point numbers.

Keywords: encoding of numbers, DNA strands, operations with the DNA-chain, DNA computing