diff --git a/html/index.html b/html/index.html
index a79a9ae..5bb23f3 100644
--- a/html/index.html
+++ b/html/index.html
@@ -143,16 +143,18 @@
 						Numeric representation:
 					</div>
 					<div class="col-12">
-						<!--<label>
+						<label>
 							Numbers:
 							<select id="selNumbers">
-								<option value="native">Native</option>
+								<!--<option value="native">Native</option>
 								<option value="rational">Rational</option>
 								<option value="fixed" selected>Fixed</option>
-								<option value="gfixed">Fixed (guarded)</option>
+								<option value="gfixed">Fixed (guarded)</option>-->
+								<option value="rational">Rational</option>
+								<option value="float64">Float (64-bit)</option>
 							</select>
 						</label>
-						<label>
+						<!--<label>
 							Decimal places (if Numbers = Fixed):
 							<input type="number" id="txtDP" value="5" min="0" style="width: 3em;">
 						</label>-->
diff --git a/html/index.js b/html/index.js
index fdadf99..be38a58 100644
--- a/html/index.js
+++ b/html/index.js
@@ -61,6 +61,10 @@ worker.onmessage = function(evt) {
 	}
 }
 
+worker.onerror = function(evt) {
+	alert('An unknown error occurred while counting the votes. More details may be available in the browser\'s developer console.');
+}
+
 async function clickCount() {
 	if (document.getElementById('bltFile').files.length === 0) {
 		return;
@@ -93,6 +97,7 @@ async function clickCount() {
 		'type': 'countElection',
 		'electionData': electionData,
 		'optsStr': optsStr,
-		'filePath': filePath
+		'filePath': filePath,
+		'numbers': document.getElementById('selNumbers').value,
 	});
 }
diff --git a/html/worker.js b/html/worker.js
index 39f82cd..8feadfa 100644
--- a/html/worker.js
+++ b/html/worker.js
@@ -10,36 +10,43 @@ initWasm();
 
 onmessage = function(evt) {
 	if (evt.data.type === 'countElection') {
+		let numbers;
+		if (evt.data.numbers === 'rational') {
+			numbers = 'Rational';
+		} else if (evt.data.numbers === 'float64') {
+			numbers = 'NativeFloat64';
+		}
+		
 		// Init election
-		let election = wasm.election_from_blt_Rational(evt.data.electionData);
+		let election = wasm['election_from_blt_' + numbers](evt.data.electionData);
 		
 		// Init results table
-		postMessage({'type': 'initResultsTable', 'content': wasm.init_results_table_Rational(election)});
+		postMessage({'type': 'initResultsTable', 'content': wasm['init_results_table_' + numbers](election)});
 		
 		// Init STV options
 		let opts = wasm.STVOptions.new.apply(null, evt.data.optsStr);
 		
 		// Describe count
-		postMessage({'type': 'describeCount', 'content': wasm.describe_count_Rational(evt.data.filePath, election, opts)});
+		postMessage({'type': 'describeCount', 'content': wasm['describe_count_' + numbers](evt.data.filePath, election, opts)});
 		
 		// Step election
-		let state = wasm.CountStateRational.new(election);
-		wasm.count_init_Rational(state, opts);
+		let state = wasm['CountState' + numbers].new(election);
+		wasm['count_init_' + numbers](state, opts);
 		
-		postMessage({'type': 'updateResultsTable', 'result': wasm.update_results_table_Rational(1, state, opts)});
-		postMessage({'type': 'updateStageComments', 'comment': wasm.update_stage_comments_Rational(state)});
+		postMessage({'type': 'updateResultsTable', 'result': wasm['update_results_table_' + numbers](1, state, opts)});
+		postMessage({'type': 'updateStageComments', 'comment': wasm['update_stage_comments_' + numbers](state)});
 		
 		for (let stageNum = 2;; stageNum++) {
-			let isDone = wasm.count_one_stage_Rational(state, opts);
+			let isDone = wasm['count_one_stage_' + numbers](state, opts);
 			if (isDone) {
 				break;
 			}
 			
-			postMessage({'type': 'updateResultsTable', 'result': wasm.update_results_table_Rational(stageNum, state, opts)});
-			postMessage({'type': 'updateStageComments', 'comment': wasm.update_stage_comments_Rational(state)});
+			postMessage({'type': 'updateResultsTable', 'result': wasm['update_results_table_' + numbers](stageNum, state, opts)});
+			postMessage({'type': 'updateStageComments', 'comment': wasm['update_stage_comments_' + numbers](state)});
 		}
 		
-		postMessage({'type': 'updateResultsTable', 'result': wasm.finalise_results_table_Rational(state)});
-		postMessage({'type': 'finalResultSummary', 'summary': wasm.final_result_summary_Rational(state)});
+		postMessage({'type': 'updateResultsTable', 'result': wasm['finalise_results_table_' + numbers](state)});
+		postMessage({'type': 'finalResultSummary', 'summary': wasm['final_result_summary_' + numbers](state)});
 	}
 }
diff --git a/src/numbers/native.rs b/src/numbers/native.rs
index 3d7deae..8c884e2 100644
--- a/src/numbers/native.rs
+++ b/src/numbers/native.rs
@@ -208,9 +208,7 @@ impl ops::SubAssign<&NativeFloat64> for NativeFloat64 {
 }
 
 impl ops::MulAssign<&NativeFloat64> for NativeFloat64 {
-	fn mul_assign(&mut self, _rhs: &NativeFloat64) {
-		todo!()
-	}
+	fn mul_assign(&mut self, rhs: &NativeFloat64) { self.0 *= &rhs.0 }
 }
 
 impl ops::DivAssign<&NativeFloat64> for NativeFloat64 {