In natural numbers with a single digit of 2, there are______ A square number

In natural numbers with a single digit of 2, there are______ A square number

Look at the digit 1 × 1, digit 12 × 2, digit 43 × 3, digit 94 × 4, digit 65 × 5, 56 × 6, digit 67 × 7, digit 98 × 8, digit 49 × 9, digit 10 × 0, and digit 0. Therefore, the digit of a square number cannot be 2, and there are 0 squares in the natural number of digit 2, so the answer is: 0