Convert foot to inches:
1 foot = 12 inches
23 feet ⇒ 23 feet × 12 inches/ft = 276 inches
Divide:
276 ÷ 9 = 30 pieces with remainder
Remainder = 276 - (9×30) ⇒ 276 - 270 = 6
ANSWER: There will be 6 inches long remaining in length after cutting the string into 30 pieces equal lenght of 9 inches each.
