 
 <prompt> N'akụkọ nke mbụ, ụgbọelu nwere ike ịgba aha nke ụgbọelu. N'akụkọ nke abụọ, ụgbọelu nwere ọdịkarịa 10 nwere ike ịgba. N'akụkọ nke atọ, ụgbọelu nwere ọdịkarịa 20 nwere ike ịgba n'akụkọ abụọ. Ọ bụghị nke ụgbọelu nwere ọdịkarịa n'akụkọ bụ 80, ma ụgbọelu nwere ọdịkarịa 10 n'akụkọ nke mbụ, tinyere ihe ọ bụla nke ụgbọelu nwere ọdịkarịa n'akụkọ anọ. <response>: N'akụkọ nke mbụ, ụlọ ọzọ nwere ike ịgba aha nke ụlọ ahụ, ọ bụrụ na ụlọ ahụ na-aga 10*2=20 aha.
N'akụkọ nke abụọ, ụlọ ọzọ nwere aha 10 nwepụrụ n'ime, jiri aha 20+10=30.
N'akụkọ nke atọ, ụlọ ọzọ nwere aha 20 nwepụrụ n'ime aha nke ọkara abụọ, jiri aha 20+30=50.
Ọ bụghị nke a bụ aha ụlọ ahụ nwepụrụ n'ime a ma 80, ha nwepụrụ 80-50=30 aha n'ime aha anọ.

Aha dị ka: 30. 