Question

Determinați ultima cifră a sumei s = 5 ^ 129 + 7 ^ 26​

Answer 1

Răspuns:

$u( {5}^{129} ) = 5$

${7}^{1} = 7 \\ {7}^{2} = 49 \\ {7}^{3} = 343 \\ {7}^{4} = 2401 \\ {7}^{5} = 14807$

$26 \div 4 = 6 \: rest \: 2$

$= > u( {7}^{26} ) = 9$

$5 + 9 = 14$

$= > u(suma \: data) = 4$