anchor.diff:     check 
         <@@ 
            let dt = DateTime(2014,9,11).AddMinutes(v)
  -         float dt.Ticks
  +         // TODO: Worrying that we need to round to 5 sig. figs. here. 
  +         //       Perhaps the number type in JS isn't precise enough for this implementation.
  +         toSigFigs 5 (float dt.Ticks) 
         @@>
   
   [<TestCase(100.); TestCase(-100.); TestCase(0.)>]
  
positive.code:    check 
        <@@ 
           let dt = DateTime(2014,9,11).AddSeconds(v)
           float dt.Ticks
        @@>
  
  [<TestCase(100.); TestCase(-100.); TestCase(0.)>]
  
negative.code:          let res1 = dt.Subtract(ts).Ticks
           let res2 = (dt - ts).Ticks
           if (res1 = res2)
           // TODO: Worrying that we need to round to 5 sig. figs. here. 
           //       Perhaps the number type in JS isn't precise enough for this implementation.
           then toSigFigs 5 (float res2)
           else failwith "synonyms don't match"
        @@>
  
  