diff --git a/src/main/kotlin/ch/kleis/lcaplugin/ui/toolwindow/DisplayedNumber.kt b/src/main/kotlin/ch/kleis/lcaplugin/ui/toolwindow/DisplayedNumber.kt
index 6aebccbaa..13827a18a 100644
--- a/src/main/kotlin/ch/kleis/lcaplugin/ui/toolwindow/DisplayedNumber.kt
+++ b/src/main/kotlin/ch/kleis/lcaplugin/ui/toolwindow/DisplayedNumber.kt
@@ -1,5 +1,6 @@
 package ch.kleis.lcaplugin.ui.toolwindow
 
+import arrow.core.flatten
 import arrow.core.replicate
 import com.intellij.util.containers.tail
 import kotlin.math.*
@@ -15,7 +16,10 @@ class DisplayedNumber(
     init {
         fun prepareNonZero(v: Double): Pair<Int, List<Int>> {
             val w = abs(v)
-            val positionalExponent = ceil(log10(w)).toInt()
+            val e = ceil(log10(w)).toInt()
+            val positionalExponent =
+                if (w == 10.0.pow(e)) e
+                else e - 1
             val shift = nbSignificantDigits - positionalExponent
             val reversedDigits = ArrayList<Int>()
             var u = floor(w * (10.0.pow(shift))).toInt()
@@ -23,13 +27,13 @@ class DisplayedNumber(
                 reversedDigits.add(u.mod(10))
                 u /= 10
             }
-            val digits = reversedDigits.reversed()
+            val digits = reversedDigits.reversed().take(nbSignificantDigits)
 
             if (digits.tail().take(nbSignificantDigits - 1).all { it == 9 }) {
                 val hd = digits[0]
                 if (hd == 9) {
                     val zeros = listOf(0).replicate(nbSignificantDigits - 2).flatten()
-                    return positionalExponent to listOf(1, 0) + zeros
+                    return positionalExponent + 1 to listOf(1, 0) + zeros
                 }
                 val zeros = listOf(0).replicate(nbSignificantDigits - 1).flatten()
                 return positionalExponent to listOf(hd + 1) + zeros
@@ -40,7 +44,7 @@ class DisplayedNumber(
 
         if (value == 0.0) {
             isPositive = true
-            positionalExponent = 1
+            positionalExponent = 0
             digits = IntRange(1, nbSignificantDigits).map { 0 }
         } else {
             val (e, d) = prepareNonZero(value)
@@ -50,7 +54,7 @@ class DisplayedNumber(
         }
     }
 
-    fun getExponent(): Int {
+    fun getPositionalExponent(): Int {
         return positionalExponent
     }
 
@@ -77,43 +81,40 @@ class DisplayedNumber(
     }
 
     override fun toString(): String {
-        if (value == 0.0) {
-            return "0"
-        }
-
-        if (isPowerOf10()) {
-            return renderPowerOf10()
-        }
-
-        val midpoint = when {
-            positionalExponent <= -nbSignificantDigits + 1 -> 1
-            -nbSignificantDigits + 1 < positionalExponent
-                && positionalExponent < nbSignificantDigits -> positionalExponent
-
-            else -> nbSignificantDigits
-        }
-        val displayedExponent = when {
-            -nbSignificantDigits + 1 < positionalExponent
-                && positionalExponent < nbSignificantDigits -> 0
-
-            else -> positionalExponent - midpoint
-        }
-
-        val head = when {
-            midpoint <= 0 -> emptyList()
-            else -> digits.subList(0, midpoint)
-        }.joinToString("").ifEmpty { "0" }
-        val tail = when {
-            midpoint <= 0 -> {
-                val prefix = listOf(0).replicate(-midpoint).flatten()
-                prefix + digits.take(nbSignificantDigits)
+        return when {
+            positionalExponent in -2 .. -1 -> {
+                val hd = listOf(0).replicate(-positionalExponent-1).flatten()
+                    .joinToString("")
+                    .let { "0.$it" }
+                val tl = digits.take(nbSignificantDigits - positionalExponent + 1)
+                    .dropLastWhile { it == 0 }
+                    .joinToString("")
+                val sign = if (isPositive) "" else "-"
+                "$sign$hd$tl"
             }
-            else -> digits.subList(midpoint, nbSignificantDigits)
-        }.dropLastWhile { it == 0 }.joinToString("")
-
-        val sign = if (isPositive) "" else "-"
-        val e = if (displayedExponent == 0) "" else "E$displayedExponent"
-        return if (tail.isEmpty()) "$sign$head$e" else "$sign${head}.$tail$e"
+            positionalExponent in 0..2 -> {
+                val midpoint = min(positionalExponent + 1, nbSignificantDigits)
+                val hd = digits.subList(0, midpoint)
+                    .joinToString("")
+                val tl = digits.subList(midpoint, nbSignificantDigits)
+                    .dropLastWhile { it == 0 }
+                    .joinToString("")
+                    .let { if (it.isEmpty()) "" else ".$it"}
+                val sign = if (isPositive) "" else "-"
+                "$sign$hd$tl"
+            }
+            else -> {
+                val hd = digits.subList(0, 1)
+                    .joinToString("")
+                val tl = digits.subList(1, nbSignificantDigits)
+                    .dropLastWhile { it == 0 }
+                    .joinToString("")
+                    .let { if (it.isEmpty()) "" else ".$it"}
+                val sign = if (isPositive) "" else "-"
+                val e = "E$positionalExponent"
+                "$sign$hd$tl$e"
+            }
+        }
     }
 }
 
diff --git a/src/test/kotlin/ch/kleis/lcaplugin/ui/toolwindow/DisplayedNumberTest.kt b/src/test/kotlin/ch/kleis/lcaplugin/ui/toolwindow/DisplayedNumberTest.kt
index 85e6a1c41..d240c9905 100644
--- a/src/test/kotlin/ch/kleis/lcaplugin/ui/toolwindow/DisplayedNumberTest.kt
+++ b/src/test/kotlin/ch/kleis/lcaplugin/ui/toolwindow/DisplayedNumberTest.kt
@@ -5,16 +5,119 @@ import kotlin.test.assertEquals
 
 class DisplayedNumberTest {
     @Test
-    fun test_displayedNumber() {
-        // given
-        val value = 1.2345
+    fun test_positive_displayedNumber() {
+        listOf(
+            0.0012345 to -3 to "123",
+            0.012345 to -2 to "123",
+            0.12345 to -1 to "123",
+            1.2345 to 0 to "123",
+            12.345 to 1 to "123",
+            123.45 to 2 to "123",
+            1234.5 to 3 to "123",
+            12345.0 to 4 to "123",
+
+            0.0 to 0 to "000",
+            0.0001 to -4 to "100",
+            0.001 to -3 to "100",
+            0.01 to -2 to "100",
+            0.1 to -1 to "100",
+            1.0 to 0 to "100",
+            10.0 to 1 to "100",
+            100.0 to 2 to "100",
+            1000.0 to 3 to "100",
+
+            0.000999 to -3 to "100",
+            0.00999 to -2 to "100",
+            0.0999 to -1 to "100",
+            0.999 to 0 to "100",
+            9.99 to 1 to "100",
+            99.9 to 2 to "100",
+            999.0 to 3 to "100",
+
+            0.001001 to -3 to "100",
+            0.01001 to -2 to "100",
+            0.1001 to -1 to "100",
+            1.001 to 0 to "100",
+            10.01 to 1 to "100",
+            100.1 to 2 to "100",
+            1001.0 to 3 to "100",
+
+            0.0002999 to -4 to "300",
+            0.003999 to -3 to "400",
+            0.04999 to -2 to "500",
+            0.5999 to -1 to "600",
+            6.999 to 0 to "700",
+            79.90 to 1 to "800",
+            899.9 to 2 to "900",
+        ).forEach {
+            val value = it.first.first
+            val expectedPositionalExponent = it.first.second
+            val expectedDigits = it.second
+
+            val actual = DisplayedNumber(value)
+            val actualPositionalExponent = actual.getPositionalExponent()
+            val actualDigits = actual.getDigits().joinToString("")
+
+            assertEquals(expectedPositionalExponent to expectedDigits, actualPositionalExponent to actualDigits, "value = $value")
+        }
+    }
 
-        // when
-        val actual = DisplayedNumber(value, nbSignificantDigits = 3)
+    @Test
+    fun test_negative_displayedNumber() {
+        listOf(
+            0.0012345 to -3 to "123",
+            0.012345 to -2 to "123",
+            0.12345 to -1 to "123",
+            1.2345 to 0 to "123",
+            12.345 to 1 to "123",
+            123.45 to 2 to "123",
+            1234.5 to 3 to "123",
+            12345.0 to 4 to "123",
+
+            0.0 to 0 to "000",
+            0.0001 to -4 to "100",
+            0.001 to -3 to "100",
+            0.01 to -2 to "100",
+            0.1 to -1 to "100",
+            1.0 to 0 to "100",
+            10.0 to 1 to "100",
+            100.0 to 2 to "100",
+            1000.0 to 3 to "100",
+
+            0.000999 to -3 to "100",
+            0.00999 to -2 to "100",
+            0.0999 to -1 to "100",
+            0.999 to 0 to "100",
+            9.99 to 1 to "100",
+            99.9 to 2 to "100",
+            999.0 to 3 to "100",
+
+            0.001001 to -3 to "100",
+            0.01001 to -2 to "100",
+            0.1001 to -1 to "100",
+            1.001 to 0 to "100",
+            10.01 to 1 to "100",
+            100.1 to 2 to "100",
+            1001.0 to 3 to "100",
 
-        // then
-        assertEquals(1, actual.getExponent())
-        assertEquals(listOf(1, 2, 3), actual.getDigits())
+            0.0002999 to -4 to "300",
+            0.003999 to -3 to "400",
+            0.04999 to -2 to "500",
+            0.5999 to -1 to "600",
+            6.999 to 0 to "700",
+            79.90 to 1 to "800",
+            899.9 to 2 to "900",
+        ).forEach {
+            val value = -it.first.first
+            val expectedPositionalExponent = it.first.second
+            val expectedDigits = it.second
+
+            val actual = DisplayedNumber(value)
+            val actualPositionalExponent = actual.getPositionalExponent()
+            val actualDigits = actual.getDigits().joinToString("")
+
+            assertEquals(expectedPositionalExponent to expectedDigits, actualPositionalExponent to actualDigits, "value = $value")
+        }
     }
 
     @Test
@@ -37,6 +140,14 @@ class DisplayedNumberTest {
             99.9 to "100",
             999.0 to "1E3",
 
+            0.001001 to "1E-3",
+            0.01001 to "0.01",
+            0.1001 to "0.1",
+            1.001 to "1",
+            10.01 to "10",
+            100.1 to "100",
+            1001.0 to "1E3",
+
             0.003999 to "4E-3",
             0.04999 to "0.05",
             0.5999 to "0.6",
@@ -49,7 +160,10 @@ class DisplayedNumberTest {
             0.0123 to "0.0123",
             0.123 to "0.123",
             1.2345 to "1.23",
-            12345.123 to "123E2",
+            12.345 to "12.3",
+            123.45 to "123",
+            1234.5 to "1.23E3",
+            12345.123 to "1.23E4",
 
             -0.0 to "0",
             -0.0001 to "-1E-4",
@@ -63,7 +177,7 @@ class DisplayedNumberTest {
             -0.0123 to "-0.0123",
             -0.123 to "-0.123",
             -1.2345 to "-1.23",
-            -12345.123 to "-123E2",
+            -12345.123 to "-1.23E4",
             -0.00123 to "-1.23E-3",
         ).forEach {
             val actual = DisplayedNumber(it.first).toString()