Thursday

Rocket lays a strip of tape around a rectangle of cards. "A frame for the puzzle board. How long a strip do I need?"

"Measure once, then use the formula," says Raven. "The perimeter of a rectangle is 2l + 2w. What do you notice about the letters?"

"Two of them," Rocket says. "Length and width. Two numbers go in, one comes out."

Nova hovers over the tape, her light measuring the long side. "Letters work in formulas the same way," she says. "Replace, then compute."

"And the cube box for the beans is s cubed," Raven says, holding up a small cardboard cube. "One letter, used three times."

Rocket writes both formulas on the wall. "Puzzle Post building code," he says. "Letters first, numbers after."

A formula is an expression that works for every size. Put in the measurements and it tells you the answer.

Perimeter of a rectangle: P = 2l + 2w, where l is the length and w the width. Area: A = l × w.

Volume of a cube: V = s³, where s is the side. Surface area of a cube: A = 6s², six square faces.

Replace each letter with its number, then follow the order of operations. Powers before multiplying, multiplying before adding.

These are the crew's own measurements for the Puzzle Post frames and bean boxes, in centimeters.

Frame 1 is 6 cm by 4 cm. Its perimeter is 2 × 6 + 2 × 4 = 20 cm of tape. Frame 3 is a square, and the formula still works.

Box 2 has side 3 cm. Its volume is 3 × 3 × 3 = 27 cubic cm. Its surface area is 6 × 9 = 54 sq cm.

The standard asks about a cube with side 1/2. Then s³ = 0.125 and 6s² = 1.5. Fractions follow the same order.

Frames and boxes planned. Tomorrow you see a letter as any number from a set, and review the week.