 
 <prompt> A yaro ya yi 5-level pyramid ta hanyar stacking wasu blocks. A cikin farko, ya samu 9 blocks. Don haka, a karshe rows, ya samu 2 kuma yana da blocks daga wata row dake kasa. Me ya faru ne ya yi amfani da blocks a cikin dukkan? <response>: A cikin sati na biyu, ya yi amfani da 9 - 2 = 7 blocks.
A cikin sati na uku, ya yi amfani da 7 - 2 = 5 blocks.
A cikin sati na hudu, ya yi amfani da 5 - 2 = 3 blocks.
A cikin sati na biyar, ya yi amfani da 3 - 2 = 1 block.
Saboda haka, ya yi amfani da jumla na 9 + 7 + 5 + 3 + 1 = 25 blocks.

Sami kunci: 25. 