diff --git a/core/org.eclipse.cdt.ui.tests/ui/org/eclipse/cdt/ui/tests/text/CPartitionerTest.java b/core/org.eclipse.cdt.ui.tests/ui/org/eclipse/cdt/ui/tests/text/CPartitionerTest.java
index c62cad5f33b..46e09d497be 100644
--- a/core/org.eclipse.cdt.ui.tests/ui/org/eclipse/cdt/ui/tests/text/CPartitionerTest.java
+++ b/core/org.eclipse.cdt.ui.tests/ui/org/eclipse/cdt/ui/tests/text/CPartitionerTest.java
@@ -1192,4 +1192,15 @@ public class CPartitionerTest extends TestCase {
 			assertTrue(false);
 		}
 	}
+
+	public void testNumberSeparators() {
+		try {
+			fDocument.replace(0, fDocument.getLength(), "1'123'456\n0x1000'1000\n0111'1000\n0xAABB'CCDD");
+			ITypedRegion[] result = fDocument.computePartitioning(0, fDocument.getLength());
+			TypedRegion[] expectation = { new TypedRegion(0, 43, IDocument.DEFAULT_CONTENT_TYPE) };
+			checkPartitioning(expectation, result);
+		} catch (BadLocationException x) {
+			assertTrue(false);
+		}
+	}
 }
diff --git a/core/org.eclipse.cdt.ui.tests/ui/org/eclipse/cdt/ui/tests/text/NumberRuleTest.java b/core/org.eclipse.cdt.ui.tests/ui/org/eclipse/cdt/ui/tests/text/NumberRuleTest.java
index 71b19f67fd2..536626b2578 100644
--- a/core/org.eclipse.cdt.ui.tests/ui/org/eclipse/cdt/ui/tests/text/NumberRuleTest.java
+++ b/core/org.eclipse.cdt.ui.tests/ui/org/eclipse/cdt/ui/tests/text/NumberRuleTest.java
@@ -125,6 +125,14 @@ public class NumberRuleTest extends TestCase {
 		assertNoNumber("+ 9");
 	}
 
+	public void testSeparators() {
+		assertNumber("1'123'456");
+		assertNumber("0x1000'1000");
+		assertNumber("0111'1000");
+		assertNumber("0xAABB'CCDD");
+		assertNoNumber("'");
+	}
+
 	/**
 	 * Validate that given string is recognized as a number.
 	 * @param string
diff --git a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/text/FastCPartitionScanner.java b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/text/FastCPartitionScanner.java
index c38dd0526d1..21fcd848045 100644
--- a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/text/FastCPartitionScanner.java
+++ b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/text/FastCPartitionScanner.java
@@ -62,6 +62,7 @@ public final class FastCPartitionScanner implements IPartitionTokenScanner, ICPa
 	private static final int BACKSLASH_BACKSLASH = 7; // postfix for STRING, CHARACTER
 	private static final int RAW_STRING_R = 8; // prefix for RAW_STRING
 	private static final int IDENT = 9;
+	private static final int NUMBER = 10;
 
 	/** The scanner. */
 	private final BufferedDocumentScanner fScanner = new BufferedDocumentScanner(1000); // faster implementation
@@ -311,6 +312,11 @@ public final class FastCPartitionScanner implements IPartitionTokenScanner, ICPa
 					}
 
 				case '\'':
+					if (fLast == NUMBER) {
+						// C++14 digit separator
+						fTokenOffset++;
+						break;
+					}
 					fLast = NONE; // ignore fLast
 					if (fTokenLength > 0) {
 						return preFix(CCODE, CHARACTER, NONE, 1);
@@ -373,10 +379,14 @@ public final class FastCPartitionScanner implements IPartitionTokenScanner, ICPa
 					break;
 				default:
 					if ('a' <= ch && ch <= 'z' || 'A' <= ch && ch <= 'Z' || ch == '_') {
-						fLast = IDENT;
+						if (fLast != NUMBER)
+							fLast = IDENT;
 						fTokenOffset++;
 					} else if ('0' <= ch && ch <= '9' && fLast == IDENT) {
 						fTokenOffset++;
+					} else if (('0' <= ch && ch <= '9') || ch == '.') {
+						fLast = NUMBER;
+						fTokenOffset++;
 					} else {
 						consume();
 					}
diff --git a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/text/NumberRule.java b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/text/NumberRule.java
index 20fc9e96b4f..2cb82d0b281 100644
--- a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/text/NumberRule.java
+++ b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/text/NumberRule.java
@@ -58,7 +58,7 @@ public class NumberRule implements IRule {
 					// hexnumber starting with [+-]?0[xX]
 					do {
 						ch = scanner.read();
-					} while (isHexNumberPart((char) ch));
+					} while (isHexDigitOrSeparator(ch));
 					scanner.unread();
 					return token;
 				}
@@ -72,12 +72,12 @@ public class NumberRule implements IRule {
 				// need at least one digit
 				do {
 					ch = scanner.read();
-				} while (Character.isDigit((char) ch));
+				} while (isDecDigitOrSeparator(ch));
 				if (ch == '.' && startCh != '.') {
 					// fraction
 					do {
 						ch = scanner.read();
-					} while (Character.isDigit((char) ch));
+					} while (isDecDigitOrSeparator(ch));
 				}
 				if (ch == 'e' || ch == 'E') {
 					// exponent
@@ -85,7 +85,7 @@ public class NumberRule implements IRule {
 					if (ch == '-' || ch == '+' || Character.isDigit((char) ch)) {
 						do {
 							ch = scanner.read();
-						} while (Character.isDigit((char) ch));
+						} while (isDecDigitOrSeparator(ch));
 					}
 				}
 				scanner.unread();
@@ -107,13 +107,21 @@ public class NumberRule implements IRule {
 		return ch == '-' || ch == '+' || ch == '.' || Character.isDigit((char) ch);
 	}
 
+	/**
+	 * Checks if part of decimal number;
+	 * @param ch Char to check.
+	 * @return <b>true</b>
+	 */
+	private boolean isDecDigitOrSeparator(int ch) {
+		return Character.isDigit((char) ch) || (ch == '\'');
+	}
+
 	/**
 	 * Checks if part of hex number;
 	 * @param ch Char to check.
 	 * @return <b>true</b>
 	 */
-	private boolean isHexNumberPart(int ch) {
-		return Character.isDigit((char) ch) || ch == 'a' || ch == 'b' || ch == 'c' || ch == 'd' || ch == 'e'
-				|| ch == 'f' || ch == 'A' || ch == 'B' || ch == 'C' || ch == 'D' || ch == 'E' || ch == 'F';
+	private boolean isHexDigitOrSeparator(int ch) {
+		return Character.isDigit((char) ch) || (ch >= 'a' && ch <= 'f') || (ch >= 'A' && ch <= 'F') || (ch == '\'');
 	}
 }