diff --git a/src/display.rs b/src/display.rs
index 63463e2..2b2659c 100644
--- a/src/display.rs
+++ b/src/display.rs
@@ -299,6 +299,10 @@ impl DispalyState {
         self[7].off();
         self[8].off();
     }
+
+    pub fn slice(&mut self, start: usize, len: usize) -> &mut [Segment] {
+        &mut self.0.as_mut_slice()[start..(start + len)]
+    }
 }
 
 // Show data on segment display
diff --git a/src/main.rs b/src/main.rs
index 533fc04..63dc0ee 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -192,22 +192,47 @@ impl Show for NumberInput {
     fn show(&self, display: &mut DispalyState) {
         display.off();
         display[1].dp();
-        if !self.enter_exponent && self.significant_pos < DISPLAY_SEGMENTS_SIG {
-            display[self.significant_pos + 1].prompt();
-        } else if self.enter_exponent && self.exponent_pos < DISPLAY_SEGMENTS_EXP {
-            display[DISPLAY_SEGMENTS_SIG + 2 + self.exponent_pos].prompt();
-        }
+
+        let (minus, sig) = display.slice(0, 1 + DISPLAY_SEGMENTS_SIG).split_at_mut(1);
+
         if self.minus {
-            display[DISPLAY_SEGMENT_SIG_MINUS].minus();
+            minus[0].minus();
         }
-        for i in 0..self.significant_pos {
-            display[DISPLAY_SEGMENT_SIG_MINUS + 1 + i].num(self.significant[i]);
+
+        for (seg, num) in sig
+            .iter_mut()
+            .zip(self.significant.iter())
+            .take(self.significant_pos)
+        {
+            seg.num(*num);
         }
+
+        if !self.enter_exponent {
+            if let Some(seg) = sig.get_mut(self.significant_pos) {
+                seg.prompt();
+            }
+        }
+
+        let (minus, exp) = display
+            .slice(1 + DISPLAY_SEGMENTS_SIG, 1 + DISPLAY_SEGMENTS_EXP)
+            .split_at_mut(1);
+
         if self.minus_exponent {
-            display[DISPLAY_SEGMENT_EXP_MINUS].minus();
+            minus[0].minus();
         }
-        for i in 0..self.exponent_pos {
-            display[DISPLAY_SEGMENT_EXP_MINUS + 1 + i].num(self.exponent[i]);
+
+        for (seg, num) in exp
+            .iter_mut()
+            .zip(self.exponent.iter())
+            .take(self.exponent_pos)
+        {
+            seg.num(*num);
+        }
+
+        if self.enter_exponent {
+            if let Some(seg) = exp.get_mut(self.exponent_pos) {
+                seg.prompt();
+            }
         }
     }
 }