Toán Lớp 6: 3/1.5+3/5.9+3/9.13+…+3/45.49
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Toán Lớp 6: 3/1.5+3/5.9+3/9.13+…+3/45.49
Comments ( 1 )
$\frac{3}{1.5}$ + $\frac{3}{5.9}$ + $\frac{3}{9.13}$ +….+$\frac{3}{45.49}$
= $\frac{3}{4}$ . ( $1$ – $\frac{1}{5}$ + $\frac{1}{5}$ – $\frac{1}{9}$ +$\frac{1}{9}$ – $\frac{1}{13}$ + ….. + $\frac{1}{45}$ –
= $\frac{3}{4}$ . ($1$ – $\frac{1}{49}$ )
=$\frac{3}{4}$ . ( $\frac{49}{49}$ – $\frac{1}{49}$ )
= $\frac{3}{4}$ . $\frac{48}{49}$
= $\frac{36}{49}$
$Táo^^$