diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
--- a/CHANGELOG.markdown
+++ b/CHANGELOG.markdown
@@ -1,3 +1,7 @@
+0.7.0.1
+-------
+* Removed a couple of unnecessary `Fractional` constraints.
+
 0.7
 ---
 * Corrected the definition of `mignitude`.
diff --git a/intervals.cabal b/intervals.cabal
--- a/intervals.cabal
+++ b/intervals.cabal
@@ -1,5 +1,5 @@
 name:              intervals
-version:           0.7
+version:           0.7.0.1
 synopsis:          Interval Arithmetic
 description:
   A 'Numeric.Interval.Interval' is a closed, convex set of floating point values.
diff --git a/src/Numeric/Interval.hs b/src/Numeric/Interval.hs
--- a/src/Numeric/Interval.hs
+++ b/src/Numeric/Interval.hs
@@ -12,6 +12,7 @@
 module Numeric.Interval
   ( Interval
   , (...)
+  , (+/-)
   , interval
   , whole
   , empty
@@ -31,6 +32,8 @@
   , magnitude
   , mignitude
   , distance
+  , inflate, deflate
+  , scale, symmetric
   , contains
   , isSubsetOf
   , certainly, (<!), (<=!), (==!), (>=!), (>!)
diff --git a/src/Numeric/Interval/Internal.hs b/src/Numeric/Interval/Internal.hs
--- a/src/Numeric/Interval/Internal.hs
+++ b/src/Numeric/Interval/Internal.hs
@@ -20,6 +20,7 @@
 module Numeric.Interval.Internal
   ( Interval(..)
   , (...)
+  , (+/-)
   , interval
   , whole
   , empty
@@ -39,6 +40,8 @@
   , magnitude
   , mignitude
   , distance
+  , inflate, deflate
+  , scale, symmetric
   , contains
   , isSubsetOf
   , certainly, (<!), (<=!), (==!), (>=!), (>!)
@@ -77,7 +80,11 @@
   {-# INLINE foldMap #-}
 
 infix 3 ...
+infixl 6 +/-
 
+(+/-) :: (Num a, Ord a) => a -> a -> Interval a
+a +/- b = a - b ... a + b
+
 negInfinity :: Fractional a => a
 negInfinity = (-1)/0
 {-# INLINE negInfinity #-}
@@ -261,6 +268,69 @@
 distance :: (Num a, Ord a) => Interval a -> Interval a -> a
 distance i1 i2 = mignitude (i1 - i2)
 
+-- | Inflate an interval by enlarging it at both ends.
+--
+-- >>> inflate 3 (-1 ... 7)
+-- -4 ... 10
+--
+-- >>> inflate (-2) (0 ... 4)
+-- -2 ... 6
+--
+-- >>> inflate 1 empty
+-- Empty
+inflate :: (Num a, Ord a) => a -> Interval a -> Interval a
+inflate x y = symmetric x + y
+
+-- | Deflate an interval by shrinking it from both ends.
+--
+-- >>> deflate 3.0 (-4.0 ... 10.0)
+-- -1.0 ... 7.0
+--
+-- >>> deflate 2.0 (-1.0 ... 1.0)
+-- Empty
+--
+-- >>> deflate 1.0 empty
+-- Empty
+deflate :: (Fractional a, Ord a) => a -> Interval a -> Interval a
+deflate _ Empty               = Empty
+deflate x (I a b) | a' <= b'  = I a' b'
+                  | otherwise = Empty
+  where
+    a' = a + x
+    b' = b - x
+
+-- | Scale an interval about its midpoint.
+--
+-- >>> scale 1.1 (-6.0 ... 4.0)
+-- -6.5 ... 4.5
+--
+-- >>> scale (-2.0) (-1.0 ... 1.0)
+-- Empty
+--
+-- >>> scale 3.0 empty
+-- Empty
+scale :: (Fractional a, Ord a) => a -> Interval a -> Interval a
+scale _ Empty = Empty
+scale x i = a ... b where
+  h = x * width i / 2
+  mid = midpoint i
+  a = mid - h
+  b = mid + h
+
+-- | Construct a symmetric interval.
+--
+-- >>> symmetric 3
+-- -3 ... 3
+--
+-- >>> symmetric (-2)
+-- -2 ... 2
+symmetric :: (Num a, Ord a) => a -> Interval a
+symmetric x | a <= b    = I a b
+            | otherwise = I b a
+  where
+    a = negate x
+    b = x
+
 instance (Num a, Ord a) => Num (Interval a) where
   I a b + I a' b' = (a + a') ... (b + b')
   _ + _ = Empty
@@ -592,7 +662,7 @@
 --
 -- >>> intersection (1 ... 10 :: Interval Double) (5 ... 15 :: Interval Double)
 -- 5.0 ... 10.0
-intersection :: (Fractional a, Ord a) => Interval a -> Interval a -> Interval a
+intersection :: Ord a => Interval a -> Interval a -> Interval a
 intersection x@(I a b) y@(I a' b')
   | x /=! y   = Empty
   | otherwise = I (max a a') (min b b')
diff --git a/src/Numeric/Interval/Kaucher.hs b/src/Numeric/Interval/Kaucher.hs
--- a/src/Numeric/Interval/Kaucher.hs
+++ b/src/Numeric/Interval/Kaucher.hs
@@ -38,6 +38,8 @@
   , magnitude
   , mignitude
   , distance
+  , inflate, deflate
+  , scale, symmetric
   , contains
   , isSubsetOf
   , certainly, (<!), (<=!), (==!), (>=!), (>!)
@@ -272,6 +274,53 @@
 -- NaN
 distance :: (Num a, Ord a) => Interval a -> Interval a -> a
 distance i1 i2 = mignitude (i1 - i2)
+
+-- | Inflate an interval by enlarging it at both ends.
+--
+-- >>> inflate 3 (-1 ... 7)
+-- -4 ... 10
+--
+-- >>> inflate (-2) (0 ... 4)
+-- 2 ... 2
+inflate :: (Num a, Ord a) => a -> Interval a -> Interval a
+inflate x y = symmetric x + y
+
+-- | Deflate an interval by shrinking it from both ends.
+--
+-- >>> deflate 3.0 (-4.0 ... 10.0)
+-- -1.0 ... 7.0
+--
+-- >>> deflate 2.0 (-1.0 ... 1.0)
+-- 1.0 ... -1.0
+deflate :: (Fractional a, Ord a) => a -> Interval a -> Interval a
+deflate x (I a b) = I a' b'
+  where
+    a' = a + x
+    b' = b - x
+
+-- | Scale an interval about its midpoint.
+--
+-- >>> scale 1.1 (-6.0 ... 4.0)
+-- -6.5 ... 4.5
+--
+-- >>> scale (-2.0) (-1.0 ... 1.0)
+-- 2.0 ... -2.0
+scale :: (Fractional a, Ord a) => a -> Interval a -> Interval a
+scale x i = I a b where
+  h = x * width i / 2
+  mid = midpoint i
+  a = mid - h
+  b = mid + h
+
+-- | Construct a symmetric interval.
+--
+-- >>> symmetric 3
+-- -3 ... 3
+--
+-- >>> symmetric (-2)
+-- 2 ... -2
+symmetric :: (Num a, Ord a) => a -> Interval a
+symmetric x = negate x ... x
 
 instance (Num a, Ord a) => Num (Interval a) where
   I a b + I a' b' = (a + a') ... (b + b')
diff --git a/src/Numeric/Interval/NonEmpty.hs b/src/Numeric/Interval/NonEmpty.hs
--- a/src/Numeric/Interval/NonEmpty.hs
+++ b/src/Numeric/Interval/NonEmpty.hs
@@ -42,6 +42,8 @@
   , certainly, (<!), (<=!), (==!), (>=!), (>!)
   , possibly, (<?), (<=?), (==?), (>=?), (>?)
   , clamp
+  , inflate, deflate
+  , scale, symmetric
   , idouble
   , ifloat
   ) where
diff --git a/src/Numeric/Interval/NonEmpty/Internal.hs b/src/Numeric/Interval/NonEmpty/Internal.hs
--- a/src/Numeric/Interval/NonEmpty/Internal.hs
+++ b/src/Numeric/Interval/NonEmpty/Internal.hs
@@ -41,6 +41,8 @@
   , certainly, (<!), (<=!), (==!), (>=!), (>!)
   , possibly, (<?), (<=?), (==?), (>=?), (>?)
   , clamp
+  , inflate, deflate
+  , scale, symmetric
   , idouble
   , ifloat
   ) where
@@ -471,7 +473,7 @@
 --
 -- >>> intersection (1 ... 10 :: Interval Double) (5 ... 15 :: Interval Double)
 -- Just (5.0 ... 10.0)
-intersection :: (Fractional a, Ord a) => Interval a -> Interval a -> Maybe (Interval a)
+intersection :: Ord a => Interval a -> Interval a -> Maybe (Interval a)
 intersection x@(I a b) y@(I a' b')
   | x /=! y   = Nothing
   | otherwise = Just $ I (max a a') (min b b')
@@ -654,6 +656,56 @@
   | x < a     = a
   | x > b     = b
   | otherwise = x
+
+-- | Inflate an interval by enlarging it at both ends.
+--
+-- >>> inflate 3 (-1 ... 7)
+-- -4 ... 10
+--
+-- >>> inflate (-2) (0 ... 4)
+-- -2 ... 6
+inflate :: (Num a, Ord a) => a -> Interval a -> Interval a
+inflate x y = symmetric x + y
+
+-- | Deflate an interval by shrinking it from both ends.
+-- Note that in cases that would result in an empty interval, the result is a singleton interval at the midpoint.
+--
+-- >>> deflate 3.0 (-4.0 ... 10.0)
+-- -1.0 ... 7.0
+--
+-- >>> deflate 2.0 (-1.0 ... 1.0)
+-- 0.0 ... 0.0
+deflate :: (Fractional a, Ord a) => a -> Interval a -> Interval a
+deflate x i@(I a b) | a' <= b'  = I a' b'
+                    | otherwise = singleton m
+  where
+    a' = a + x
+    b' = b - x
+    m = midpoint i
+
+-- | Scale an interval about its midpoint.
+--
+-- >>> scale 1.1 (-6.0 ... 4.0)
+-- -6.5 ... 4.5
+--
+-- >>> scale (-2.0) (-1.0 ... 1.0)
+-- -2.0 ... 2.0
+scale :: (Fractional a, Ord a) => a -> Interval a -> Interval a
+scale x i = a ... b where
+  h = x * width i / 2
+  mid = midpoint i
+  a = mid - h
+  b = mid + h
+
+-- | Construct a symmetric interval.
+--
+-- >>> symmetric 3
+-- -3 ... 3
+--
+-- >>> symmetric (-2)
+-- -2 ... 2
+symmetric :: (Num a, Ord a) => a -> Interval a
+symmetric x = negate x ... x
 
 -- | id function. Useful for type specification
 --