diff --git a/app/src/main/java/keijumt/devandroid/viewmodel/AsyncViewModel.kt b/app/src/main/java/keijumt/devandroid/viewmodel/AsyncViewModel.kt
index 9a976b1..6f675f3 100644
--- a/app/src/main/java/keijumt/devandroid/viewmodel/AsyncViewModel.kt
+++ b/app/src/main/java/keijumt/devandroid/viewmodel/AsyncViewModel.kt
@@ -1,6 +1,9 @@
 package keijumt.devandroid.viewmodel
 
 import android.os.AsyncTask
+import io.reactivex.Single
+import io.reactivex.rxkotlin.Singles
+import io.reactivex.rxkotlin.subscribeBy
 import keijumt.devandroid.common.Task
 import kotlinx.coroutines.experimental.async
 import kotlinx.coroutines.experimental.launch
@@ -29,5 +32,17 @@
     }
 
     fun rx() {
+        val disposable = Singles
+                .zip(rxCalc(3), rxCalc(5)) { num1, num2 -> num1 * num2 }
+                .subscribeBy(
+                        onSuccess = {
+                            println(it)
+                        }
+                )
+        addDisposable(disposable)
+    }
+
+    fun rxCalc(num: Int) = Single.create<Int> {
+        it.onSuccess(num * num)
     }
 }
\ No newline at end of file