In javascript, when you use decimals for addition, subtraction, multiplication, and division, you will find that the result is sometimes followed by a long decimal, which can complicate the operation and affect the result. The reason is as follows: in javascript, there are always many decimal places in the calculation of data with decimal.

function numAdd(num1, num2) {
var baseNum, baseNum1, baseNum2;
try {
baseNum1 = num1.toString().split(".")[1].length;
} catch (e) {
baseNum1 = 0;
}
try {
baseNum2 = num2.toString().split(".")[1].length;
} catch (e) {
baseNum2 = 0;
}
baseNum = Math.pow(10, Math.max(baseNum1, baseNum2));
return (num1 * baseNum + num2 * baseNum) / baseNum;
};

function numSub(num1, num2) {
var baseNum, baseNum1, baseNum2;
var precision;//  precision
try {
baseNum1 = num1.toString().split(".")[1].length;
} catch (e) {
baseNum1 = 0;
}
try {
baseNum2 = num2.toString().split(".")[1].length;
} catch (e) {
baseNum2 = 0;
}
baseNum = Math.pow(10, Math.max(baseNum1, baseNum2));
precision = (baseNum1 >= baseNum2) ? baseNum1 : baseNum2;
return ((num1 * baseNum - num2 * baseNum) / baseNum).toFixed(precision);
};

function numMulti(num1, num2) {
var baseNum = 0;
try {
baseNum += num1.toString().split(".")[1].length;
} catch (e) {
}
try {
baseNum += num2.toString().split(".")[1].length;
} catch (e) {
}
return Number(num1.toString().replace(".", "")) * Number(num2.toString().replace(".", "")) / Math.pow(10, baseNum);
};

function numDiv(num1, num2) {
var baseNum1 = 0, baseNum2 = 0;
var baseNum3, baseNum4;
try {
baseNum1 = num1.toString().split(".")[1].length;
} catch (e) {
baseNum1 = 0;
}
try {
baseNum2 = num2.toString().split(".")[1].length;
} catch (e) {
baseNum2 = 0;
}
with (Math) {
baseNum3 = Number(num1.toString().replace(".", ""));
baseNum4 = Number(num2.toString().replace(".", ""));
return (baseNum3 / baseNum4) * pow(10, baseNum2 - baseNum1);
}
};