float flt [4] = {0.0};
char str [4][8] = {"21.54", "543.28", "965.27", "56.75"};
char cal [8];

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);

  for (uint8_t i = 0; i < 4; i ++){
    strcpy (cal, str[i]);//string copy function
    flt[i] = atof(cal);//ascii to float function
    Serial.print("flt value ");
    Serial.print(i);
    Serial.print(" = ");
    Serial.println(flt[i]);
  }
  Serial.print("flt value 0 + flt value 1 = ");
  Serial.println(flt[0] + flt[1]);//Math calc proves convertion from string
  Serial.print("flt value 2 + flt value 3 = ");
  Serial.println(flt[2] + flt[3]);

}

void loop() {
  // put your main code here, to run repeatedly:

}