Sending data sensor form slave to master via bluetooth (arduino to another)

Excuss me guys...

I am work to sending data form arduino to another via bluetooth communication. Yesterday I can sending data from master to slave( this data is to operating on/off LED). and then I was constrained to send sensor data from slave Bluetooth to master Bluetooth, anyone can help me? here this is my code to operating led

//PROGRAM MASTER BLUETOOTH
#define button1 5
#define button2 6
#define button3 7
int buttonState1 = 0;
int buttonState2 = 0;
int buttonState3 = 0;

void setup() {
  pinMode(button1, INPUT_PULLUP);
  pinMode(button2, INPUT_PULLUP);
  pinMode(button3, INPUT_PULLUP);
  Serial.begin(38400);
}

void loop() {  
 delay(100);
 buttonState1 = digitalRead(button1);
 buttonState2 = digitalRead(button2);
 buttonState3 = digitalRead(button3);
 //PUSH BUTTON 1
 if (buttonState1 == HIGH) {
   Serial.println('a');
 }
 else {
   Serial.println('b');
 }  
//PUSH BUTTON 2
 if (buttonState2 == HIGH) {
   Serial.println('c');
 }
 else {
   Serial.println('d');
 } 
//PUSH BUTTON 3
  if (buttonState3 == HIGH) {
   Serial.println('e');
 }
 else {
   Serial.println('f');
 } }
//PROGRAM SLAVE BLUETOOTH
#define ledPin1 2
#define ledPin2 3
#define ledPin3 4

int state = 0;

void setup() {
  pinMode(ledPin1, OUTPUT);
  pinMode(ledPin2, OUTPUT);
  pinMode(ledPin3, OUTPUT);
  
  digitalWrite(ledPin1, LOW);
  digitalWrite(ledPin2, LOW);
  digitalWrite(ledPin3, LOW);

  
  Serial.begin(38400); 
}

void loop() {
 if(Serial.available() > 0){ 
    state = Serial.read(); 
    Serial.write(state);
 }
 // LED1
 if (state == 'a') {
  digitalWrite(ledPin1, LOW); // LED ON
  state = 0;
 }
 else if (state == 'b') {
  digitalWrite(ledPin1, HIGH); // LED ON
  state = 0;
 }

//LED2
if (state == 'c') {
  digitalWrite(ledPin2, LOW); // LED ON
  state = 0;
 }
 else if (state == 'd') {
  digitalWrite(ledPin2, HIGH); // LED ON
  state = 0;
 }

//LED3
 if (state == 'e') {
  digitalWrite(ledPin3, LOW); // LED ON
  state = 0;
 }
 else if (state == 'f') {
  digitalWrite(ledPin3, HIGH); // LED ON
  state = 0;
 }
}