matchExponent

immutable a = Decimal(123456, 3);
assert(matchExponent(a, a) == tuple(a, a));

immutable b = Decimal(7890120, 4);
assert(matchExponent(a, b) == tuple(Decimal(1234560, 4), b));
assert(matchExponent(b, a) == tuple(b, Decimal(1234560, 4)));