diff --git a/poincare/src/square_root.cpp b/poincare/src/square_root.cpp
index cdefee1a5..29094e952 100644
--- a/poincare/src/square_root.cpp
+++ b/poincare/src/square_root.cpp
@@ -44,11 +44,46 @@ Expression SquareRoot::shallowReduce(ExpressionNode::ReductionContext reductionC
       return e;
     }
   }
-  Expression c = childAtIndex(0);
-  if (c.deepIsMatrix(reductionContext.context())) {
+  Expression child = childAtIndex(0);
+  if (child.deepIsMatrix(reductionContext.context())) {
     return replaceWithUndefinedInPlace();
   }
-  Power p = Power::Builder(c, Rational::Builder(1, 2));
+
+  // Test if we are in a case like sqrt(a +- sqrt(b)) where a and b are rational
+  if (child.type() == ExpressionNode::Type::Addition && child.numberOfChildren() == 2) {
+    bool subtraction = child.numberOfChildren() == 2 && child.childAtIndex(1).type() == ExpressionNode::Type::Multiplication && child.childAtIndex(1).numberOfChildren() == 2 && child.childAtIndex(1).childAtIndex(0).type() == ExpressionNode::Type::Rational && child.childAtIndex(1).childAtIndex(0).sign(reductionContext.context()) == ExpressionNode::Sign::Negative;
+    Expression a = child.childAtIndex(0);
+    Expression b = subtraction && child.childAtIndex(1).childAtIndex(0).convert<Rational>().isMinusOne() ? child.childAtIndex(1).childAtIndex(1) : child.childAtIndex(1);
+    // If root have been simplified in x * sqrt(y), we say that b is sqrt(x^2 * y)
+    if (b.type() == ExpressionNode::Type::Multiplication && b.numberOfChildren() == 2 && b.childAtIndex(0).type() == ExpressionNode::Type::Rational && b.childAtIndex(0).type() == ExpressionNode::Type::Rational && b.childAtIndex(1).type() == ExpressionNode::Type::Power && b.childAtIndex(1).childAtIndex(0).type() == ExpressionNode::Type::Rational && b.childAtIndex(1).childAtIndex(1).type() == ExpressionNode::Type::Rational && b.childAtIndex(1).childAtIndex(1).convert<Rational>().isHalf()) {
+      b = Power::Builder(Multiplication::Builder(Power::Builder(b.childAtIndex(0).clone(), Rational::Builder(2, 1)).shallowReduce(reductionContext), b.childAtIndex(1).childAtIndex(0).clone()).shallowReduce(reductionContext), Rational::Builder(1, 2));
+    }
+    if (a.type() == ExpressionNode::Type::Rational && b.type() == ExpressionNode::Type::Power && b.childAtIndex(0).type() == ExpressionNode::Type::Rational && b.childAtIndex(1).type() == ExpressionNode::Type::Rational && b.childAtIndex(1).convert<Rational>().isHalf()) {
+      Expression a0 = a.clone();
+      Expression a1 = b.childAtIndex(0).clone();
+      // There is a simplification (wikipedia)
+      Expression rr = Subtraction::Builder(Power::Builder(a0, Rational::Builder(2, 1)).shallowReduce(reductionContext), a1).shallowReduce(reductionContext);
+      if (a0.sign(reductionContext.context()) != ExpressionNode::Sign::Negative && rr.sign(reductionContext.context()) != ExpressionNode::Sign::Negative) {
+        Expression r = Power::Builder(rr, Rational::Builder(1, 2)).shallowReduce(reductionContext);
+        if (r.type() == ExpressionNode::Type::Rational) {
+          Expression c = Division::Builder(Addition::Builder(a0.clone(), r.clone()).shallowReduce(reductionContext), Rational::Builder(2, 1)).shallowReduce(reductionContext);
+          Expression d = Division::Builder(Subtraction::Builder(a0.clone(), r.clone()).shallowReduce(reductionContext), Rational::Builder(2, 1)).shallowReduce(reductionContext);
+
+          Expression result;
+          if (subtraction) {
+            result = Subtraction::Builder(Power::Builder(c, Rational::Builder(1, 2)).shallowReduce(reductionContext), Power::Builder(d, Rational::Builder(1, 2)).shallowReduce(reductionContext));
+          } else {
+            result = Addition::Builder(Power::Builder(c, Rational::Builder(1, 2)).shallowReduce(reductionContext), Power::Builder(d, Rational::Builder(1, 2)).shallowReduce(reductionContext));
+          }
+
+          replaceWithInPlace(result);
+          return result.shallowReduce(reductionContext);
+        }
+      }
+    }
+  }
+
+  Power p = Power::Builder(child, Rational::Builder(1, 2));
   replaceWithInPlace(p);
   return p.shallowReduce(reductionContext);
 }