Tính nhanh: a) <span class="MathJax_Preview" style="color: inherit;"><span class="MJXp-math" id="MJXp-Span-1"><span class="MJXp-mstyle" id="MJXp-Span-2"><span class="MJXp-mn" id="MJXp-Span-3">45</span><span class="MJXp-mo" id="MJXp-Span-4" style="margin-left: 0em; margin-right: 0.222em;">,</span><span class="MJXp-mn" id="MJXp-Span-5">5</span><span class="MJXp-mo" id="MJXp-Span-6" style="margin-left: 0.267em; margin-right: 0.267em;">×</span><span class="MJXp-mn" id="MJXp-Span-7">21</span><span class="MJXp-mo" id="MJXp-Span-8" style="margin-left: 0.267em; margin-right: 0.267em;">+</span><span class="MJXp-mn" id="MJXp-Span-9">54</span><span class="MJXp-mo" id="MJXp-Span-10" style="margin-left: 0em; margin-right: 0.222em;">,</span><span class="MJXp-mn" id="MJXp-Span-11">5</span><span class="MJXp-mo" id="MJXp-Span-12" style="margin-left: 0.267em; margin-right: 0.267em;">×</span><span class="MJXp-mn" id="MJXp-Span-13">21</span><span class="MJXp-mo" id="MJXp-Span-14" style="margin-left: 0.333em; margin-right: 0.333em;">=</span><span class="MJXp-mo" id="MJXp-Span-15" style="margin-left: 0em; margin-right: 0.222em;">.</span><span class="MJXp-mo" id="MJXp-Span-16" style="margin-left: 0em; margin-right: 0.222em;">.</span><span class="MJXp-mo" id="MJXp-Span-17" style="margin-left: 0em; margin-right: 0.222em;">.</span></span></span></span><script type="math/tex" id="MathJax-Element-1">\Large 45,5\times21+54,5\times21=...</script> b) \(\Large 14

Tính nhanh: a) 45,5×21+54,5×21=... b) \(\Large 14

4.5/5

Tác giả: Thầy Tùng

Đăng ngày: 18 Aug 2022

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Câu hỏi:

Tính nhanh:

a) 45,5×21+54,5×21=...

b) 145,5×5,0933,5×5,0912×5,09=...

Đáp án án đúng là: A

Lời giải chi tiết:

Học sinh tự giải.

a)21×(45,5+54,5)=21×100=2100

b) 5,09×(145,533,512)=5,09×100=509