diff --git a/operator-fraction.go b/operator-fraction.go
index b979721..9f6f13b 100644
--- a/operator-fraction.go
+++ b/operator-fraction.go
@@ -7,7 +7,6 @@ package expr
 //https://www.youmath.it/lezioni/algebra-elementare/lezioni-di-algebra-e-aritmetica-per-scuole-medie/553-dalle-frazioni-a-numeri-decimali.html
 
 import (
-	"errors"
 	"fmt"
 )
 
@@ -41,7 +40,7 @@ func evalFraction(ctx ExprContext, opTerm *term) (v any, err error) {
 		return
 	}
 	if den == 0 {
-		err = errors.New("division by zero")
+		err = opTerm.errDivisionByZero()
 		return
 	}
 
diff --git a/operator-prod.go b/operator-prod.go
index 6adeadf..1deaf35 100644
--- a/operator-prod.go
+++ b/operator-prod.go
@@ -5,7 +5,6 @@
 package expr
 
 import (
-	"errors"
 	"strings"
 )
 
@@ -69,7 +68,7 @@ func divValues(opTerm *term, leftValue, rightValue any) (v any, err error) {
 		if IsFloat(leftValue) || IsFloat(rightValue) {
 			d := numAsFloat(rightValue)
 			if d == 0.0 {
-				err = errors.New("division by zero")
+				err = opTerm.errDivisionByZero()
 			} else {
 				v = numAsFloat(leftValue) / d
 			}
@@ -78,11 +77,36 @@ func divValues(opTerm *term, leftValue, rightValue any) (v any, err error) {
 		} else {
 			leftInt, _ := leftValue.(int64)
 			if rightInt, _ := rightValue.(int64); rightInt == 0 {
-				err = errors.New("division by zero")
+				err = opTerm.errDivisionByZero()
 			} else {
 				v = leftInt / rightInt
 			}
 		}
+	} else if IsString(leftValue) && IsString(rightValue) {
+		source := leftValue.(string)
+		sep := rightValue.(string)
+		v = ListFromStrings(strings.Split(source, sep))
+	} else if IsString(leftValue) && IsInteger(rightValue) {
+		source := leftValue.(string)
+		partSize := int(rightValue.(int64))
+		if partSize == 0 {
+			err = opTerm.errDivisionByZero()
+		} else {
+			partCount := len(source) / partSize
+			remainder := len(source) % partSize
+			listSize := partCount
+			if remainder > 0 {
+				listSize++
+			}
+			parts := make([]any, 0, listSize)
+			for i := 0; i < partCount; i++ {
+				parts = append(parts, source[i*partSize:(i+1)*partSize])
+			}
+			if remainder > 0 {
+				parts = append(parts, source[len(source)-remainder:])
+			}
+			v = newList(parts)
+		}
 	} else {
 		err = opTerm.errIncompatibleTypes(leftValue, rightValue)
 	}
@@ -121,7 +145,7 @@ func evalDivideAsFloat(ctx ExprContext, floatDivTerm *term) (v any, err error) {
 	if isNumOrFract(leftValue) && isNumOrFract(rightValue) {
 		d := numAsFloat(rightValue)
 		if d == 0.0 {
-			err = errors.New("division by zero")
+			err = floatDivTerm.errDivisionByZero()
 		} else {
 			v = numAsFloat(leftValue) / d
 		}
@@ -146,7 +170,7 @@ func remainderValues(opTerm *term, leftValue, rightValue any) (v any, err error)
 	if IsInteger(leftValue) && IsInteger(rightValue) {
 		rightInt, _ := rightValue.(int64)
 		if rightInt == 0 {
-			err = errors.New("division by zero")
+			err = opTerm.errDivisionByZero()
 		} else {
 			leftInt, _ := leftValue.(int64)
 			v = leftInt % rightInt
diff --git a/t_fractions_test.go b/t_fractions_test.go
index c4c38a1..6d8fc15 100644
--- a/t_fractions_test.go
+++ b/t_fractions_test.go
@@ -25,7 +25,7 @@ func TestFractionsParser(t *testing.T) {
 		/*  12 */ {`builtin "math.arith"; add(1:2, 1.0, 2)`, float64(3.5), nil},
 		/*  13 */ {`builtin "math.arith"; mul(1:2, 2:3)`, newFraction(2, 6), nil},
 		/*  14 */ {`builtin "math.arith"; mul(1:2, 1.0, 2)`, float64(1.0), nil},
-		/*  15 */ {`1:0`, nil, `division by zero`},
+		/*  15 */ {`1:0`, nil, `[1:3] division by zero`},
 		/*  16 */ {`fract(-0.5)`, newFraction(-1, 2), nil},
 		/*  17 */ {`fract("")`, (*FractionType)(nil), `bad syntax`},
 		/*  18 */ {`fract("-1")`, newFraction(-1, 1), nil},
@@ -34,7 +34,7 @@ func TestFractionsParser(t *testing.T) {
 		/*  21 */ {`fract(1,0)`, nil, `fract(): division by zero`},
 		/*  22 */ {`string(1:2)`, "1:2", nil},
 		/*  23 */ {`1+1:2+0.5`, float64(2), nil},
-		/*  24 */ {`1:(2-2)`, nil, `division by zero`},
+		/*  24 */ {`1:(2-2)`, nil, `[1:3] division by zero`},
 		/*  25 */ {`[0,1][1-1]:1`, newFraction(0, 1), nil},
 	}
 	// runTestSuiteSpec(t, section, inputs, 25)
diff --git a/t_parser_test.go b/t_parser_test.go
index 7d385b2..e9a1aa4 100644
--- a/t_parser_test.go
+++ b/t_parser_test.go
@@ -78,8 +78,8 @@ func TestGeneralParser(t *testing.T) {
 		/*  64 */ {`"1.5" != `, nil, `[1:8] infix operator "!=" requires two non-nil operands, got 1`},
 		/*  65 */ {"+1.5", float64(1.5), nil},
 		/*  66 */ {"+", nil, `[1:2] prefix operator "+" requires one non-nil operand`},
-		/*  67 */ {"4 / 0", nil, `division by zero`},
-		/*  68 */ {"4.0 / 0", nil, `division by zero`},
+		/*  67 */ {"4 / 0", nil, `[1:4] division by zero`},
+		/*  68 */ {"4.0 / 0", nil, `[1:6] division by zero`},
 		/*  69 */ {"4.0 / \n2", float64(2.0), nil},
 		/*  70 */ {`123`, int64(123), nil},
 		/*  71 */ {`1.`, float64(1.0), nil},
diff --git a/t_strings_test.go b/t_strings_test.go
index 0b8e049..50a05f4 100644
--- a/t_strings_test.go
+++ b/t_strings_test.go
@@ -16,6 +16,12 @@ func TestStringsParser(t *testing.T) {
 		/*  4 */ {`"uno" * (2+1)`, `unounouno`, nil},
 		/*  5 */ {`"abc"[1]`, `b`, nil},
 		/*  6 */ {`#"abc"`, int64(3), nil},
+		/*  7 */ {`"192.168.0.240" / "."`, newListA("192", "168", "0", "240"), nil},
+		/*  8 */ {`("192.168.0.240" / ".")[1]`, "168", nil},
+		/*  9 */ {`"AF3B0Dz" / 2`, newListA("AF", "3B", "0D", "z"), nil},
+		/* 10 */ {`"AF3B0Dz" / 0`, nil, "[1:12] division by zero"},
 	}
+
+	// runTestSuiteSpec(t, "String", inputs, 8)
 	runTestSuite(t, "String", inputs)
 }