Wierd error while compiling my program and a module using makefile

This is the error when I run make:

Undefined symbols for architecture arm64:
"\_add", referenced from:
\_main in a4-1-989722.o
ld: symbol(s) not found for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: \*\*\* \[a4-1\] Error 1

note (one of the functions in my module is add()

This is the makefile:

CC = gcc
CFLAGS = -Wall -Wextra -pedantic
TARGET = a4-1
DEP1 = myMath

all:    $(TARGET)

debug:  CFLAGS += -DDBUG
debug:  $(TARGET)

&(TARGET): $(TARGET).c $(DEP1).o
$(CC) $(CFLAGS) $(DEP1).o -o $(TARGET) $(TARGET).c

$(DEP1).o: $(DEP1).c
$(CC) $(CFLAGS) -c $(DEP1).c

clean:
rm $(TARGET) *.o

This is the module .c file:

#include <stdio.h>
#include <stdlib.h>

int add(int x, int y)
{
    return(x + y);
}

This is the module .h file:

int add(int, int);