1. Only one inaccurate digit should be kept in the effective digit, so when recording the measurement data, only the last effective digit is inaccurate.

2, in the inaccurate figures, pay special attention to the situation of 0. 0 is a valid number between the number and the end. If 0.078 and 0.78 have nothing to do with decimal points, they are both two digits. 506 and 220 are all three digits. So: the effective number is from the first non-zero number on the left of a number to the last number. All figures are significant figures of this figure. The significant bit of (1) 35.76 is 76, the significant bit is 2(2) 0.0 1426 and the significant bit is 1426. The number of significant digits is 3. Supplement: If the number of significant digits of 0.0000 is this "number", how many digits are significant, starting from the previous decimal point, except the number that is not 0.