diff --git a/quad10/fenomens/lab/p1/P1-exercici-1.f90 b/quad10/fenomens/lab/p1/P1-exercici-1.f90
new file mode 100644
index 0000000..df09b6b
--- /dev/null
+++ b/quad10/fenomens/lab/p1/P1-exercici-1.f90
@@ -0,0 +1,26 @@
+program p1e1
+  implicit none
+  integer*4 :: SEED, i, NRAND
+  real*8 :: x, sum1, sum2, sigma, genrand_real2
+
+  SEED = 23456
+  NRAND = 50000
+
+  call init_genrand(SEED)
+
+  sum1 = 0.0d0
+  sum2 = 0.0d0
+
+  do i = 1, NRAND
+    x = genrand_real2()
+    write (*, *) i, x
+    sum1 = sum1 + x
+    sum2 = sum2 + x*x
+  enddo
+
+  sum1 = sum1/real(NRAND)
+  sum2 = sum2/real(NRAND)
+  sigma = dsqrt(sum2 - sum1*sum1)
+
+  write (*, *) sum1, sigma
+endprogram p1e1