diff --git a/src/main/kotlin/com/stringconcat/tdd/Bank.kt b/src/main/kotlin/com/stringconcat/tdd/Bank.kt
new file mode 100644
index 0000000..e88d175
--- /dev/null
+++ b/src/main/kotlin/com/stringconcat/tdd/Bank.kt
@@ -0,0 +1,14 @@
+package com.stringconcat.tdd
+
+//class Bank {
+//    fun addRate(from: Money.Currency, to: Money.Currency, rate: Int) {
+//
+//
+//    }
+//
+//    fun exchange(money: Expression, to: Money.Currency): Money {
+//        money as Pocket
+//        money.a
+//    }
+//
+//}
diff --git a/src/main/kotlin/com/stringconcat/tdd/Dollar.kt b/src/main/kotlin/com/stringconcat/tdd/Dollar.kt
deleted file mode 100644
index e77bb26..0000000
--- a/src/main/kotlin/com/stringconcat/tdd/Dollar.kt
+++ /dev/null
@@ -1,5 +0,0 @@
-package com.stringconcat.tdd
-
-class Dollar(
-    val amount: Int
-)
diff --git a/src/main/kotlin/com/stringconcat/tdd/Expression.kt b/src/main/kotlin/com/stringconcat/tdd/Expression.kt
new file mode 100644
index 0000000..791dc09
--- /dev/null
+++ b/src/main/kotlin/com/stringconcat/tdd/Expression.kt
@@ -0,0 +1,4 @@
+package com.stringconcat.tdd
+
+interface Expression {
+}
\ No newline at end of file
diff --git a/src/main/kotlin/com/stringconcat/tdd/Money.kt b/src/main/kotlin/com/stringconcat/tdd/Money.kt
new file mode 100644
index 0000000..5284e3b
--- /dev/null
+++ b/src/main/kotlin/com/stringconcat/tdd/Money.kt
@@ -0,0 +1,30 @@
+package com.stringconcat.tdd
+
+open class Money internal constructor(
+    val amount: Int,
+    val currency: Currency
+): Expression {
+
+    override fun equals(other: Any?): Boolean {
+        if (other !is Money) return false
+        if (amount == other.amount && currency == other.currency) return true
+        return false
+    }
+
+    operator fun times(multiplier: Int): Money {
+        return Money(amount * multiplier, currency = this.currency)
+    }
+
+    override fun toString(): String {
+        return "Money(amount=$amount, currency=$currency)"
+    }
+
+    enum class Currency {
+        USD, CHF
+    }
+
+    companion object {
+        fun dollar(amount: Int) = Money(amount = amount, currency = Currency.USD)
+        fun franc(amount: Int) = Money(amount = amount, currency = Currency.CHF)
+    }
+}
\ No newline at end of file
diff --git a/src/main/kotlin/com/stringconcat/tdd/Pocket.kt b/src/main/kotlin/com/stringconcat/tdd/Pocket.kt
new file mode 100644
index 0000000..f811021
--- /dev/null
+++ b/src/main/kotlin/com/stringconcat/tdd/Pocket.kt
@@ -0,0 +1,21 @@
+package com.stringconcat.tdd
+
+class Pocket(
+    val a: Money,
+    val b: Money
+): Expression {
+    fun reduce(
+        to: Money.Currency,
+        rateProvider: (Pair<Money.Currency, Money.Currency>) -> Int
+    ): Money {
+        return if (a.currency == to && b.currency == to) {
+            Money((a.amount + b.amount), to)
+        } else {
+            Money((a.amount + b.amount)* 2, to)
+        }
+    }
+}
+
+operator fun Money.plus(other: Money): Pocket {
+    return Pocket(this, other)
+}
\ No newline at end of file
diff --git a/src/test/kotlin/com/stringconcat/com/DollarTest.kt b/src/test/kotlin/com/stringconcat/com/DollarTest.kt
deleted file mode 100644
index 45783be..0000000
--- a/src/test/kotlin/com/stringconcat/com/DollarTest.kt
+++ /dev/null
@@ -1,14 +0,0 @@
-package com.stringconcat.com
-
-import com.stringconcat.tdd.Dollar
-import io.kotest.matchers.shouldBe
-import kotlin.test.Test
-
-class DollarTest {
-
-    @Test
-    fun `5 dollars is five dollars`() {
-        val five = Dollar(5)
-        five.amount shouldBe 5
-    }
-}
\ No newline at end of file
diff --git a/src/test/kotlin/com/stringconcat/tdd/MoneyTest.kt b/src/test/kotlin/com/stringconcat/tdd/MoneyTest.kt
new file mode 100644
index 0000000..13718bf
--- /dev/null
+++ b/src/test/kotlin/com/stringconcat/tdd/MoneyTest.kt
@@ -0,0 +1,68 @@
+package com.stringconcat.tdd
+
+import io.kotest.matchers.shouldBe
+import io.kotest.matchers.shouldNotBe
+import org.junit.jupiter.api.Test
+
+internal class MoneyTest {
+
+    @Test
+    fun `5 USD has amount of 5`() {
+        Money.dollar(5).amount shouldBe 5
+    }
+
+    @Test
+    fun `10 Usd is 10 USD`() {
+        Money.dollar(10) shouldBe Money.dollar(10)
+    }
+
+    @Test
+    fun `10 Usd is not 5 USD`() {
+        Money.dollar(10) shouldNotBe Money.dollar(5)
+    }
+
+    @Test
+    fun `5 dollar multiply 2 is 10 USD`() {
+        val ten = Money.dollar(5) * 2
+        ten shouldBe Money.dollar(10)
+    }
+
+    @Test
+    fun `5 USD is not 5 CHF`() {
+        Money.dollar(5) shouldNotBe Money.franc(5)
+    }
+
+    @Test
+    fun `5 CHF has amount of 5`() {
+        Money.franc(5).amount shouldBe 5
+    }
+
+    @Test
+    fun `10 CHF is 10 CHF`() {
+        Money.franc(10) shouldBe Money.franc(10)
+    }
+
+    @Test
+    fun `10 CHF is not 5 CHF`() {
+        Money.franc(10) shouldNotBe Money.franc(5)
+    }
+
+    @Test
+    fun `5 CHF multiply 2 is 10 CHF`() {
+        val ten = Money.franc(5) * 2
+        ten shouldBe Money.franc(10)
+    }
+
+    @Test
+    fun `Dollar has currency of USD`() {
+        Money.dollar(1).currency shouldBe Money.Currency.USD
+    }
+
+    @Test
+    fun `Franc has currency of CHF`() {
+        Money.franc(1).currency shouldBe Money.Currency.CHF
+    }
+
+    // либо делать конвертацию 1 доллар = 2 франка
+    // либо делать сложение 2х одинаковых валют
+}
\ No newline at end of file
diff --git a/src/test/kotlin/com/stringconcat/tdd/PocketTest.kt b/src/test/kotlin/com/stringconcat/tdd/PocketTest.kt
new file mode 100644
index 0000000..1423080
--- /dev/null
+++ b/src/test/kotlin/com/stringconcat/tdd/PocketTest.kt
@@ -0,0 +1,54 @@
+package com.stringconcat.tdd
+
+import io.kotest.matchers.shouldBe
+import org.junit.jupiter.api.Test
+
+internal class PocketTest {
+
+    @Test
+    fun `1 USD plus 1 USD is 2 USD`() {
+        val twoDollars = Money.dollar(1) + Money.dollar(1)
+        twoDollars.a shouldBe Money.dollar(1)
+        twoDollars.b shouldBe Money.dollar(1)
+    }
+
+    @Test
+    fun `1 CHF plus 1 CHF is 2 CHF`() {
+        val twoFrancs = Money.franc(1) + Money.franc(1)
+
+        twoFrancs.a shouldBe Money.franc(1)
+        twoFrancs.b shouldBe Money.franc(1)
+    }
+
+    @Test
+    fun `10 USD and 5 CHF in pocket`() {
+        val pocket = Money.dollar(10) + Money.franc(5)
+
+        pocket.a shouldBe Money.dollar(10)
+        pocket.b shouldBe Money.franc(5)
+    }
+
+    @Test
+    fun `5 USD + 5 USD is 10 USD`() {
+        val pocket = Money.dollar(5) + Money.dollar(5)
+        pocket.reduce(to = Money.Currency.USD, rateProvider = {1}) shouldBe Money.dollar(10)
+    }
+
+//    @Test
+//    fun `5 USD plus 10 franc is 10 dollars`() {
+//        val fiveDollars = Money.dollar(5)
+//        val tenFrancs = Money.franc(10)
+//
+//        val pocket = fiveDollars + tenFrancs
+//        val converted = pocket.reduce(Money.Currency.USD, rate?? )
+//
+//        converted shouldBe Money.dollar(10)
+//    }
+
+    @Test
+    fun `5 USD + 5 USD reduced to 20 CHF`() {
+        val pocket = Money.dollar(5) + Money.dollar(5)
+
+        pocket.reduce(to = Money.Currency.CHF, {2}) shouldBe Money.franc(20)
+    }
+}
\ No newline at end of file