diff --git a/template/variables.go b/template/variables.go
index fb32f9c3..84edee59 100644
--- a/template/variables.go
+++ b/template/variables.go
@@ -108,6 +108,9 @@ func extractVariable(value interface{}, pattern *regexp.Regexp) ([]Variable, boo
 			if r >= 'A' && r <= 'Z' {
 				return false
 			}
+			if r >= '0' && r <= '9' {
+				return false
+			}
 			if r == '_' {
 				return false
 			}
diff --git a/template/variables_test.go b/template/variables_test.go
index 00133d5a..7239b016 100644
--- a/template/variables_test.go
+++ b/template/variables_test.go
@@ -50,6 +50,15 @@ func TestExtractVariables(t *testing.T) {
 				"bar": {Name: "bar"},
 			},
 		},
+		{
+			name: "variable-without-curly-braces-and-with-number-suffix",
+			dict: map[string]interface{}{
+				"foo": "$bar_1",
+			},
+			expected: map[string]Variable{
+				"bar_1": {Name: "bar_1"},
+			},
+		},
 		{
 			name: "variable",
 			dict: map[string]interface{}{
@@ -68,6 +77,15 @@ func TestExtractVariables(t *testing.T) {
 				"bar": {Name: "bar", DefaultValue: "", Required: true},
 			},
 		},
+		{
+			name: "required-variable-with-number-suffix",
+			dict: map[string]interface{}{
+				"foo": "${bar_1?:foo}",
+			},
+			expected: map[string]Variable{
+				"bar_1": {Name: "bar_1", DefaultValue: "", Required: true},
+			},
+		},
 		{
 			name: "required-variable2",
 			dict: map[string]interface{}{
@@ -95,6 +113,24 @@ func TestExtractVariables(t *testing.T) {
 				"bar": {Name: "bar", DefaultValue: "foo"},
 			},
 		},
+		{
+			name: "default-variable-with-number-suffix",
+			dict: map[string]interface{}{
+				"foo": "${bar_1:-foo}",
+			},
+			expected: map[string]Variable{
+				"bar_1": {Name: "bar_1", DefaultValue: "foo"},
+			},
+		},
+		{
+			name: "default-variable2-with-number-suffix",
+			dict: map[string]interface{}{
+				"foo": "${bar_1-foo}",
+			},
+			expected: map[string]Variable{
+				"bar_1": {Name: "bar_1", DefaultValue: "foo"},
+			},
+		},
 		{
 			name: "multiple-values",
 			dict: map[string]interface{}{