diff --git a/kotlin/difference-of-squares/.gradle/3.5/file-changes/last-build.bin b/kotlin/difference-of-squares/.gradle/3.5/file-changes/last-build.bin
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diff --git a/kotlin/difference-of-squares/.gradle/3.5/taskHistory/taskHistory.lock b/kotlin/difference-of-squares/.gradle/3.5/taskHistory/taskHistory.lock
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diff --git a/kotlin/difference-of-squares/.gradle/buildOutputCleanup/built.bin b/kotlin/difference-of-squares/.gradle/buildOutputCleanup/built.bin
new file mode 100644
index 0000000..e69de29
diff --git a/kotlin/difference-of-squares/.gradle/buildOutputCleanup/cache.properties b/kotlin/difference-of-squares/.gradle/buildOutputCleanup/cache.properties
new file mode 100644
index 0000000..2c3f2d7
--- /dev/null
+++ b/kotlin/difference-of-squares/.gradle/buildOutputCleanup/cache.properties
@@ -0,0 +1,2 @@
+#Mon Jun 05 17:32:44 EDT 2017
+gradle.version=3.5
diff --git a/kotlin/difference-of-squares/.gradle/buildOutputCleanup/cache.properties.lock b/kotlin/difference-of-squares/.gradle/buildOutputCleanup/cache.properties.lock
new file mode 100644
index 0000000..40fdece
--- /dev/null
+++ b/kotlin/difference-of-squares/.gradle/buildOutputCleanup/cache.properties.lock
@@ -0,0 +1 @@
+
\ No newline at end of file
diff --git a/kotlin/difference-of-squares/.idea/compiler.xml b/kotlin/difference-of-squares/.idea/compiler.xml
new file mode 100644
index 0000000..b2c9a46
--- /dev/null
+++ b/kotlin/difference-of-squares/.idea/compiler.xml
@@ -0,0 +1,9 @@
+
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\ No newline at end of file
diff --git a/kotlin/difference-of-squares/.idea/gradle.xml b/kotlin/difference-of-squares/.idea/gradle.xml
new file mode 100644
index 0000000..20d2df6
--- /dev/null
+++ b/kotlin/difference-of-squares/.idea/gradle.xml
@@ -0,0 +1,19 @@
+
+
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+
+
\ No newline at end of file
diff --git a/kotlin/difference-of-squares/.idea/libraries/Gradle__junit_junit_4_12.xml b/kotlin/difference-of-squares/.idea/libraries/Gradle__junit_junit_4_12.xml
new file mode 100644
index 0000000..04c10dd
--- /dev/null
+++ b/kotlin/difference-of-squares/.idea/libraries/Gradle__junit_junit_4_12.xml
@@ -0,0 +1,11 @@
+
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+
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diff --git a/kotlin/difference-of-squares/.idea/libraries/Gradle__org_hamcrest_hamcrest_core_1_3.xml b/kotlin/difference-of-squares/.idea/libraries/Gradle__org_hamcrest_hamcrest_core_1_3.xml
new file mode 100644
index 0000000..8262f72
--- /dev/null
+++ b/kotlin/difference-of-squares/.idea/libraries/Gradle__org_hamcrest_hamcrest_core_1_3.xml
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diff --git a/kotlin/difference-of-squares/.idea/libraries/Gradle__org_jetbrains_annotations_13_0.xml b/kotlin/difference-of-squares/.idea/libraries/Gradle__org_jetbrains_annotations_13_0.xml
new file mode 100644
index 0000000..4f32fde
--- /dev/null
+++ b/kotlin/difference-of-squares/.idea/libraries/Gradle__org_jetbrains_annotations_13_0.xml
@@ -0,0 +1,11 @@
+
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\ No newline at end of file
diff --git a/kotlin/difference-of-squares/.idea/libraries/Gradle__org_jetbrains_kotlin_kotlin_stdlib_1_1_1.xml b/kotlin/difference-of-squares/.idea/libraries/Gradle__org_jetbrains_kotlin_kotlin_stdlib_1_1_1.xml
new file mode 100644
index 0000000..7b6f562
--- /dev/null
+++ b/kotlin/difference-of-squares/.idea/libraries/Gradle__org_jetbrains_kotlin_kotlin_stdlib_1_1_1.xml
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diff --git a/kotlin/difference-of-squares/.idea/libraries/Gradle__org_jetbrains_kotlin_kotlin_test_1_1_1.xml b/kotlin/difference-of-squares/.idea/libraries/Gradle__org_jetbrains_kotlin_kotlin_test_1_1_1.xml
new file mode 100644
index 0000000..1720158
--- /dev/null
+++ b/kotlin/difference-of-squares/.idea/libraries/Gradle__org_jetbrains_kotlin_kotlin_test_1_1_1.xml
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diff --git a/kotlin/difference-of-squares/.idea/libraries/Gradle__org_jetbrains_kotlin_kotlin_test_junit_1_1_1.xml b/kotlin/difference-of-squares/.idea/libraries/Gradle__org_jetbrains_kotlin_kotlin_test_junit_1_1_1.xml
new file mode 100644
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--- /dev/null
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diff --git a/kotlin/difference-of-squares/.idea/misc.xml b/kotlin/difference-of-squares/.idea/misc.xml
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--- /dev/null
+++ b/kotlin/difference-of-squares/.idea/misc.xml
@@ -0,0 +1,6 @@
+
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+
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diff --git a/kotlin/difference-of-squares/.idea/modules.xml b/kotlin/difference-of-squares/.idea/modules.xml
new file mode 100644
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diff --git a/kotlin/difference-of-squares/.idea/modules/difference-of-squares_main.iml b/kotlin/difference-of-squares/.idea/modules/difference-of-squares_main.iml
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--- /dev/null
+++ b/kotlin/difference-of-squares/.idea/modules/difference-of-squares_main.iml
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diff --git a/kotlin/difference-of-squares/.idea/modules/difference-of-squares_test.iml b/kotlin/difference-of-squares/.idea/modules/difference-of-squares_test.iml
new file mode 100644
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--- /dev/null
+++ b/kotlin/difference-of-squares/.idea/modules/difference-of-squares_test.iml
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diff --git a/kotlin/difference-of-squares/.idea/workspace.xml b/kotlin/difference-of-squares/.idea/workspace.xml
new file mode 100644
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--- /dev/null
+++ b/kotlin/difference-of-squares/.idea/workspace.xml
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+
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+ @ignore
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diff --git a/kotlin/difference-of-squares/README.md b/kotlin/difference-of-squares/README.md
new file mode 100644
index 0000000..c3e1515
--- /dev/null
+++ b/kotlin/difference-of-squares/README.md
@@ -0,0 +1,21 @@
+# Difference Of Squares
+
+Find the difference between the square of the sum and the sum of the squares of the first N natural numbers.
+
+The square of the sum of the first ten natural numbers is
+(1 + 2 + ... + 10)² = 55² = 3025.
+
+The sum of the squares of the first ten natural numbers is
+1² + 2² + ... + 10² = 385.
+
+Hence the difference between the square of the sum of the first
+ten natural numbers and the sum of the squares of the first ten
+natural numbers is 3025 - 385 = 2640.
+
+## Source
+
+Problem 6 at Project Euler [http://projecteuler.net/problem=6](http://projecteuler.net/problem=6)
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.
+
diff --git a/kotlin/difference-of-squares/build.gradle b/kotlin/difference-of-squares/build.gradle
new file mode 100644
index 0000000..16c36c0
--- /dev/null
+++ b/kotlin/difference-of-squares/build.gradle
@@ -0,0 +1,28 @@
+buildscript {
+ ext.kotlin_version = '1.1.1'
+ repositories {
+ mavenCentral()
+ }
+ dependencies {
+ classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+ }
+}
+
+apply plugin: 'kotlin'
+
+repositories {
+ mavenCentral()
+}
+
+dependencies {
+ compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
+
+ testCompile 'junit:junit:4.12'
+ testCompile "org.jetbrains.kotlin:kotlin-test-junit:$kotlin_version"
+}
+test {
+ testLogging {
+ exceptionFormat = 'full'
+ events = ["passed", "failed", "skipped"]
+ }
+}
diff --git a/kotlin/difference-of-squares/build/classes/main/Squares.class b/kotlin/difference-of-squares/build/classes/main/Squares.class
new file mode 100644
index 0000000..ffab366
Binary files /dev/null and b/kotlin/difference-of-squares/build/classes/main/Squares.class differ
diff --git a/kotlin/difference-of-squares/build/classes/test/SquaresTest.class b/kotlin/difference-of-squares/build/classes/test/SquaresTest.class
new file mode 100644
index 0000000..df6269f
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diff --git a/kotlin/difference-of-squares/build/kotlin-build/caches/version.txt b/kotlin/difference-of-squares/build/kotlin-build/caches/version.txt
new file mode 100644
index 0000000..01aabac
--- /dev/null
+++ b/kotlin/difference-of-squares/build/kotlin-build/caches/version.txt
@@ -0,0 +1 @@
+11001
\ No newline at end of file
diff --git a/kotlin/difference-of-squares/difference-of-squares.iml b/kotlin/difference-of-squares/difference-of-squares.iml
new file mode 100644
index 0000000..577f3d6
--- /dev/null
+++ b/kotlin/difference-of-squares/difference-of-squares.iml
@@ -0,0 +1,12 @@
+
+
+
+
+
+
+
+
+
+
+
+
\ No newline at end of file
diff --git a/kotlin/difference-of-squares/src/main/kotlin/.keep b/kotlin/difference-of-squares/src/main/kotlin/.keep
new file mode 100644
index 0000000..e69de29
diff --git a/kotlin/difference-of-squares/src/main/kotlin/Squares.kt b/kotlin/difference-of-squares/src/main/kotlin/Squares.kt
new file mode 100644
index 0000000..825f752
--- /dev/null
+++ b/kotlin/difference-of-squares/src/main/kotlin/Squares.kt
@@ -0,0 +1,22 @@
+class Squares(val firstNNumbers: Int) {
+ fun squareOfSum(): Int{
+ var sum: Int = 0
+ for (i in 0..firstNNumbers){
+ sum += i
+ }
+
+ return sum * sum
+ }
+
+ fun sumOfSquares(): Int{
+ var sum: Int = 0
+ for (i in 0..firstNNumbers){
+ sum += i*i
+ }
+ return sum
+ }
+
+ fun difference(): Int{
+ return squareOfSum()-sumOfSquares()
+ }
+}
\ No newline at end of file
diff --git a/kotlin/difference-of-squares/src/test/kotlin/SquaresTest.kt b/kotlin/difference-of-squares/src/test/kotlin/SquaresTest.kt
new file mode 100644
index 0000000..377952e
--- /dev/null
+++ b/kotlin/difference-of-squares/src/test/kotlin/SquaresTest.kt
@@ -0,0 +1,73 @@
+import org.junit.Test
+import org.junit.Ignore
+import kotlin.test.assertEquals
+
+class SquaresTest {
+
+
+ @Test
+ fun squareOfSum5() {
+ assertEquals(225, Squares(5).squareOfSum())
+ }
+
+
+ @Test
+ fun squareOfSum10() {
+ assertEquals(3025, Squares(10).squareOfSum())
+ }
+
+
+ @Test
+ fun squareOfSum100() {
+ assertEquals(25502500, Squares(100).squareOfSum())
+ }
+
+
+ @Test
+ fun sumOfSquares5() {
+ assertEquals(55, Squares(5).sumOfSquares())
+ }
+
+
+ @Test
+ fun sumOfSquares10() {
+ assertEquals(385, Squares(10).sumOfSquares())
+ }
+
+
+ @Test
+ fun sumOfSquares100() {
+ assertEquals(338350, Squares(100).sumOfSquares())
+ }
+
+
+ @Test
+ fun differenceOfSquares0() {
+ assertEquals(0, Squares(0).difference())
+ }
+
+
+ @Test
+ fun differenceOfSquares5() {
+ assertEquals(170, Squares(5).difference())
+ }
+
+
+ @Test
+ fun differenceOfSquares10() {
+ assertEquals(2640, Squares(10).difference())
+ }
+
+
+ @Test
+ fun differenceOfSquares100() {
+ assertEquals(25164150, Squares(100).difference())
+ }
+
+
+ @Test
+ fun consistentDifference() {
+ assertEquals(Squares(0).difference(), Squares(0).difference())
+ }
+
+}
diff --git a/kotlin/nucleotide-count/.idea/workspace.xml b/kotlin/nucleotide-count/.idea/workspace.xml
index c093b71..45eb6b2 100644
--- a/kotlin/nucleotide-count/.idea/workspace.xml
+++ b/kotlin/nucleotide-count/.idea/workspace.xml
@@ -262,7 +262,7 @@