Yarn A is a tube.
Unfold A, gently open up the yarn tube and slide your hand through to grasp the opposite end of yarn. Pull this end through to make a doubled thickness for Scarf.
Join B to one end of Scarf with a slip stitch. Work single crochet evenly spaced along one long side of Scarf. Fasten off. Weave in ends.
Cut 40-44 strands of B each about 10 in. (25 cm) long. For each fringe, hold 2 strands of yarn together and fold in half. Use crochet hook to draw fold through edge of Scarf, forming a loop. Pull ends of fringe through this loop. Pull to tighten. Make 10-11 fringes along each short end of Scarf.
Trim fringe ends evenly.