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Đáp án + Giải thích các bước giải:

a) $25,97^{}$ + $6,54^{}$ + $103,46^{}$

= $25,97^{}$ + ($6,54^{}$ + $103,46^{}$)

= $25,97^{}$ + $110^{}$

= $135,97^{}$

b) $136^{}$ x $75^{}$ + $75^{}$ x $64^{}$

= $75^{}$ x ($136^{}$ + $64^{}$)
= $75^{}$ x $200^{}$

= $15000^{}$

c) ($\frac{21}{8}$ + $\frac{1}{2}$ ) : $\frac{5}{16}$ 

= ($\frac{21.2^{}}{8.2}$ + $\frac{1.8^{}}{2.8}$) : $\frac{5}{16}$ 

Khử mẫu nên ta ⇒ $(42^{}$ + $8^{}$) : $5^{}$

                          = $50^{}$ : $5^{}$

                          = $10^{}$