diff --git a/src/expression/node/SymbolNode.js b/src/expression/node/SymbolNode.js
index 36391c751e..3f04801d3a 100644
--- a/src/expression/node/SymbolNode.js
+++ b/src/expression/node/SymbolNode.js
@@ -124,7 +124,14 @@ export const createSymbolNode = /* #__PURE__ */ factory(name, dependencies, ({ m
      * @override
      */
     _toString (options) {
-      return this.name
+      // This is a conservative approximation of the characters that can be used
+      // without quoting - we err on the side of quoting. Based on
+      // isValidLatinOrGreek from parse.js.
+      if (/^[a-zA-Z_$\u00C0-\u02AF\u0370-\u03FF\u2100-\u214F]*$/.test(this.name)) {
+        return this.name
+      } else {
+        return '`' + this.name.replace(/`/g, '\\`') + '`'
+      }
     }
 
     /**
diff --git a/src/expression/parse.js b/src/expression/parse.js
index 7961e0ba0c..90ef28692c 100644
--- a/src/expression/parse.js
+++ b/src/expression/parse.js
@@ -131,6 +131,7 @@ export const createParse = /* #__PURE__ */ factory(name, dependencies, ({
     '"': true,
     '\'': true,
     ';': true,
+    '`': true,
 
     '+': true,
     '-': true,
@@ -1335,10 +1336,14 @@ export const createParse = /* #__PURE__ */ factory(name, dependencies, ({
     let node, name
 
     if (state.tokenType === TOKENTYPE.SYMBOL ||
-        (state.tokenType === TOKENTYPE.DELIMITER && state.token in NAMED_DELIMITERS)) {
-      name = state.token
-
-      getToken(state)
+        (state.tokenType === TOKENTYPE.DELIMITER && state.token in NAMED_DELIMITERS) ||
+        state.token === '`') {
+      if (state.token === '`') {
+        name = parseQuotedSymbolToken(state)
+      } else {
+        name = state.token
+        getToken(state)
+      }
 
       if (hasOwnProperty(CONSTANTS, name)) { // true, false, null, ...
         node = new ConstantNode(CONSTANTS[name])
@@ -1356,6 +1361,28 @@ export const createParse = /* #__PURE__ */ factory(name, dependencies, ({
     return parseString(state)
   }
 
+  function parseQuotedSymbolToken (state) {
+    let name = ''
+
+    while (currentCharacter(state) !== '' && currentCharacter(state) !== '`') {
+      if (currentCharacter(state) === '\\') {
+        // escape character for closing ` - skip it
+        next(state)
+      }
+
+      name += currentCharacter(state)
+      next(state)
+    }
+
+    getToken(state)
+    if (state.token !== '`') {
+      throw createSyntaxError(state, 'End of symbol ` expected')
+    }
+    getToken(state)
+
+    return name
+  }
+
   /**
    * parse accessors:
    * - function invocation in round brackets (...), for example sqrt(2)
diff --git a/src/type/unit/Unit.js b/src/type/unit/Unit.js
index 1d1eb8da77..f443b7401f 100644
--- a/src/type/unit/Unit.js
+++ b/src/type/unit/Unit.js
@@ -759,12 +759,12 @@ export const createUnitClass = /* #__PURE__ */ factory(name, dependencies, ({
   }
 
   /**
-   * Return the numeric value of this unit if it is dimensionless, has a value, and config.predictable == false; or the original unit otherwise
+   * Return the numeric value of this unit if it is dimensionless, and has a value; or the original unit otherwise
    * @param {Unit} unit
    * @returns {number | Fraction | BigNumber | Unit}  The numeric value of the unit if conditions are met, or the original unit otherwise
    */
   function getNumericIfUnitless (unit) {
-    if (unit.equalBase(BASE_UNITS.NONE) && unit.value !== null && !config.predictable) {
+    if (unit.equalBase(BASE_UNITS.NONE) && unit.value !== null) {
       return unit.value
     } else {
       return unit
diff --git a/test/unit-tests/expression/node/SymbolNode.test.js b/test/unit-tests/expression/node/SymbolNode.test.js
index 2f3efd546d..62d0f5cb5a 100644
--- a/test/unit-tests/expression/node/SymbolNode.test.js
+++ b/test/unit-tests/expression/node/SymbolNode.test.js
@@ -123,6 +123,12 @@ describe('SymbolNode', function () {
     assert.strictEqual(s.toString(), 'foo')
   })
 
+  it('should quote stringified SymbolNodes if needed', function () {
+    assert.strictEqual(new SymbolNode('foo bar').toString(), '`foo bar`')
+    assert.strictEqual(new SymbolNode('foo_bar').toString(), 'foo_bar')
+    assert.strictEqual(new SymbolNode('foo`').toString(), '`foo\\``')
+  })
+
   it('should stringify a SymbolNode with custom toString', function () {
     // Also checks if the custom functions get passed on to the children
     const customFunction = function (node, options) {
diff --git a/test/unit-tests/expression/parse.test.js b/test/unit-tests/expression/parse.test.js
index 2bd7641926..2671f02d25 100644
--- a/test/unit-tests/expression/parse.test.js
+++ b/test/unit-tests/expression/parse.test.js
@@ -523,6 +523,38 @@ describe('parse', function () {
     })
   })
 
+  describe('symbol', function () {
+    it('should parse bare symbols', function () {
+      const scope = { foo: 3, b_a_r: 4 }
+      assert.deepStrictEqual(parseAndEval('foo*b_a_r', scope), 12)
+    })
+
+    it('should parse quoted symbols', function () {
+      const scope = { foo: 3, b_a_r: 4 }
+      assert.deepStrictEqual(parseAndEval('`foo`*`b_a_r`', scope), 12)
+    })
+
+    it('should parse quoted symbols containing arbitrary characters', function () {
+      const scope = { '-f o o-': 3, '/b a r/': 4 }
+      assert.deepStrictEqual(parseAndEval('`-f o o-`*`/b a r/`', scope), 12)
+    })
+
+    it('should allow closing backquote to be escaped', function () {
+      const scope = { 'foo`': 3, 'b`ar': 4 }
+      assert.deepStrictEqual(parseAndEval('`foo\\``*`b\\`ar`', scope), 12)
+    })
+
+    it('should allow quoted symbols to be used as function names', function () {
+      const scope = { '-f o o-': () => 3, bar: 4 }
+      assert.deepStrictEqual(parseAndEval('`-f o o-`()*bar', scope), 12)
+    })
+
+    it('should allow quoted symbol to be indexed', function () {
+      const scope = { '-f o o-': [1, 2] }
+      assert.deepStrictEqual(parseAndEval('`-f o o-`[2]', scope), 2)
+    })
+  })
+
   describe('unit', function () {
     it('should parse units', function () {
       assert.deepStrictEqual(parseAndEval('5cm'), new Unit(5, 'cm'))
diff --git a/test/unit-tests/type/unit/Unit.test.js b/test/unit-tests/type/unit/Unit.test.js
index db6822e075..d60619a214 100644
--- a/test/unit-tests/type/unit/Unit.test.js
+++ b/test/unit-tests/type/unit/Unit.test.js
@@ -556,34 +556,7 @@ describe('Unit', function () {
       assert.strictEqual(unit1.toString(), '1 N')
     })
 
-    it('should simplify units when they cancel out with {predictable: true}', function () {
-      const math2 = math.create({ predictable: true })
-      const unit1 = new math2.Unit(2, 'Hz')
-      const unit2 = new math2.Unit(2, 's')
-      const unit3 = math2.multiply(unit1, unit2)
-      assert.strictEqual(unit3.toString(), '4')
-      assert.strictEqual(unit3.simplify().units.length, 0)
-
-      const nounit = math2.evaluate('40m * 40N / (40J)')
-      assert.strictEqual(nounit.toString(), '40')
-      assert.strictEqual(nounit.simplify().units.length, 0)
-
-      const a = math2.unit('3 s^-1')
-      const b = math2.unit('4 s')
-      assert.strictEqual(math2.multiply(a, b).type, 'Unit')
-
-      const c = math2.unit('8.314 J / mol / K')
-      assert.strictEqual(math2.pow(c, 0).type, 'Unit')
-
-      const d = math2.unit('60 minute')
-      const e = math2.unit('1 s')
-      assert.strictEqual(math2.divide(d, e).type, 'Unit')
-    })
-
-    it('should convert units to appropriate _numeric_ values when they cancel out with {predictable: false}', function () {
-      const origConfig = math.config()
-      math.config({ predictable: false })
-
+    it('should convert units to appropriate _numeric_ values when they cancel out', function () {
       assert.strictEqual(typeof (math.evaluate('40 m * 40 N / (40 J)')), 'number')
 
       let bigunit = math.unit(math.bignumber(1), 'km')
@@ -608,8 +581,6 @@ describe('Unit', function () {
       const d = math.unit('60 minute')
       const e = math.unit('1 s')
       assert.strictEqual(typeof (math.divide(d, e)), 'number')
-
-      math.config(origConfig)
     })
 
     it('should simplify units according to chosen unit system', function () {