diff --git a/assets/calibration/calibration.md b/assets/calibration/calibration.md
index 2406e21..6e67a5b 100644
--- a/assets/calibration/calibration.md
+++ b/assets/calibration/calibration.md
@@ -17,5 +17,5 @@ vinTest: 12.87473, multimeter Voltage: 12.46 !
 b = (ln(12.46) - ln(5.02)) / (ln(12.87473) - ln(5.31395))
 b = 1.0273
 
-a = exp(ln(5.02) - 1.0273 \* ln(5.31395))
+a = exp(ln(5.02) - b \* ln(5.31395))
 a = 0.902573