Calculation that ignores fields with non-numbers.

New to Java, basic question:

7 fields (Sun, Mon, Tue, Wed, Thu, Fri, Sat) plus a Total Field.

I want the Total Field to:

1. calculate the sum of each field that is a number (0.1 to 12.0);

2. not include in the calculation fields that have letters (i.e. "Sun", "Mon", etc);

Note: the default values of each of the 7 fields is (ie. "Sun", "Mon", etc.)

My script breaks when the value of the fields is a non-number:

var Sun = this.getField("Sun 1");

var Mon = this.getField("Mon 1");

var Tue = this.getField("Tue 1");

var Wed = this.getField("Wed 1");

var Thu = this.getField("Thu 1");

var Fri = this.getField("Fri 1");

var Sat = this.getField("Sat 1");

var totalField = this.getField("Total Field");

var schedTotal = Number(Sun.valueAsString) + Number(Mon.valueAsString) + Number(Tue.valueAsString) + Number(Wed.valueAsString) + Number(Thu.valueAsString) + Number(Fri.valueAsString) + Number(Sat.valueAsString);

if(schedTotal > 0 && schedTotal < 37.6) {

totalField.value = schedTotal;

totalField.textColor = color.black;

Sun.strokeColor = color.transparent;

Mon.strokeColor = color.transparent;

Tue.strokeColor = color.transparent;

Wed.strokeColor = color.transparent;

Thu.strokeColor = color.transparent;

Fri.strokeColor = color.transparent;

Sat.strokeColor = color.transparent; }

else totalField.event.value = "Total";

totalField.textColour = color.ltGray;

Sun.strokeColor = color.red;

Mon.strokeColor = color.red;

Tue.strokeColor = color.red;

Wed.strokeColor = color.red;

Thu.strokeColor = color.red;

Fri.strokeColor = color.red;

Sat.strokeColor = color.red;