Analyze the provided image and extract any mathematical expressions or calculations.

Mathematical Expressions and Calculations:

• The image contains several lines that appear to be mathematical calculations or formulas.
• One line reads: S1 = 7 * 7 = 49 cm2
• Another line reads: S2 = 4 * 3 = 12 cm2
• A third line reads: S3 = 45 + 12 = 61 cm2
• There are also labels that look like measurements: 30a, 8cm, 7cm, and 8cm.
• Additionally, there are labels like P and N, and some illegible text.
• The image also includes a diagram that appears to be a geometric shape, possibly a rectangle with internal divisions, with some dimensions indicated.

Note: The units 'cut' and 'cul' are likely misinterpretations of 'cm²'. The OCR also shows some numbers and symbols that are difficult to decipher definitively.