TRICK ONE :

2⁹/₁₅ + 7⁶/₁₅

Add both whole number:

2 + 7 = 9

Now add this 2 fractions:

⁹/₁₅ + ⁶/₁₅ = ¹⁵/₁₅

Now concatinate or join the whole number value and the fraction :

9¹⁵/₁₅

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TRICK THREE :

8¹³/₁₈ + 7¹²/₄

Add both whole number:

8 + 7 = 15

Now add this 2 fractions:

¹³/₁₈ + ¹²/₄ = ⁵²⁺²¹⁶/₇₂ = ²⁶⁸/₇₂ = 3¹³/₁₈

Now concatinate or join the whole number value and the fraction :

18¹³/₁₈