You can use multiple strands of the yarns to make up a single strand of Worsted weight.
You can use Contrasting Color Worsted weight yarn for floral pattern. You can use multiple strands of the yarns to make up a single strand of Worsted weight.
Stitches and Abbreviations: (US terminology)
chain – ch
single crochet - -sc
double crochet - dc
slip stitch - sl st
cluster double crochet together - cluster dc tog
reverse sc (crab stitch)
yarn over – yo
Back post single crochet -bpsc