1. Tính
2 + 3/4 = 5 + 6/5 = 3/9 + 3 = 6/8 + 7=
2. Tính nhanh
1/3 + 3/4 + 2/3 + 1/4 =
3/4 + 3/5 + 2/8 + 4/10 =
1/10 + 2/10 + 3/10 + 4/10 + 5/10 + 6/10 + 7/10 + 8/10 + 9/10 =
4. Viết mỗi phân số sau thành tổng các phân số có tử số bằng 1 và mẫu số khác nhau:
7/12 = .../12 + ... /12 = 1/... + 1/...
17/24 = ... /24 + ... /24 = 1/ ... + 1/ ... + 1/ ...
5. Tính
7/12 - 5/12 =
13/15 - 7/15 =
9/24 - 5/24 =
3/4 - 3/12 =
16/9 - 18/27
6/7 - 5/7 + 4/7 - 3/7 + 2/7 - 1/7 =
7. Hùng có 6/7 gói kẹo, Hùng cho Hà 2/7 gói kẹo và cho Hồng 1/7 gói kẹo. Hỏi Hùng còn lại bao nhiêu phần của gói kẹo?
Bài 7:
Số phần kẹo Hùng đã cho Hà và Hồng là:
\(\dfrac{2}{7}+\dfrac{1}{7}=\dfrac{3}{7}\left(phần\right)\)
Hùng còn lại số phần của gói kẹo là:
\(\dfrac{6}{7}-\dfrac{3}{7}=\dfrac{3}{7}\left(phần\right)\)
1:
2 3/4
5 6/5
3 3/9
7 6/8
2:
1/3 + 2/3 + (3/4 + 1/4) = 2
=2
= 4 5/10
1:
\(2+\dfrac{3}{4}=\dfrac{8}{4}+\dfrac{3}{4}=\dfrac{11}{4};5+\dfrac{6}{5}=\dfrac{25}{5}+\dfrac{6}{5}=\dfrac{31}{5};\dfrac{3}{9}+3=\dfrac{1}{3}+\dfrac{9}{3}=\dfrac{10}{3}\)
2:
a: \(=\left(\dfrac{1}{3}+\dfrac{2}{3}\right)+\left(\dfrac{3}{4}+\dfrac{1}{4}\right)\\ =1+1=2\)
b: \(=\left(\dfrac{3}{4}+\dfrac{2}{8}\right)+\left(\dfrac{3}{5}+\dfrac{4}{10}\right)\\ =\left(\dfrac{6}{8}+\dfrac{2}{8}\right)+\left(\dfrac{6}{10}+\dfrac{4}{10}\right)\\ =1+1=2\)
c:\(=\left(\dfrac{1}{10}+\dfrac{9}{10}\right)+\left(\dfrac{2}{10}+\dfrac{8}{10}\right)+\left(\dfrac{3}{10}+\dfrac{7}{10}\right)+\left(\dfrac{4}{10}+\dfrac{6}{10}\right)+\dfrac{5}{10}\\ =1+1+1+1+\dfrac{5}{10}=4\dfrac{5}{10}\)
Bài 1:
\(2+\dfrac{3}{4}=\dfrac{2\times4+3}{4}=\dfrac{11}{4}\\ 5+\dfrac{6}{5}=\dfrac{5\times5+6}{5}=\dfrac{31}{5}\\ \dfrac{3}{9}+3=\dfrac{1}{3}+3=\dfrac{1+3\times3}{3}=\dfrac{10}{3}\\ \dfrac{6}{8}+7=\dfrac{3}{4}+7=\dfrac{3+7\times4}{4}=\dfrac{31}{4}\)
Bài 2:
\(\dfrac{1}{3}+\dfrac{3}{4}+\dfrac{2}{3}+\dfrac{1}{4}=\left(\dfrac{1}{3}+\dfrac{2}{3}\right)+\left(\dfrac{3}{4}+\dfrac{1}{4}\right)=1+1=2\\ \dfrac{3}{4}+\dfrac{3}{5}+\dfrac{2}{8}+\dfrac{4}{10}=\dfrac{3}{4}+\dfrac{3}{5}+\dfrac{1}{4}+\dfrac{2}{5}=\left(\dfrac{3}{4}+\dfrac{1}{4}\right)+\left(\dfrac{3}{5}+\dfrac{2}{5}\right)=1+1=2\\ \dfrac{1}{10}+\dfrac{2}{10}+\dfrac{3}{10}+\dfrac{4}{10}+\dfrac{5}{10}+\dfrac{6}{10}+\dfrac{7}{10}+\dfrac{8}{10}+\dfrac{9}{10}\\ =\left(\dfrac{1}{10}+\dfrac{9}{10}\right)+\left(\dfrac{2}{10}+\dfrac{8}{10}\right)+\left(\dfrac{3}{10}+\dfrac{7}{10}\right)+\left(\dfrac{4}{10}+\dfrac{6}{10}\right)+\dfrac{5}{10}\\ =1+1+1+1+\dfrac{1}{2}=4+\dfrac{1}{2}=\dfrac{9}{2}\)
Bài 4:
\(\dfrac{7}{12}=\dfrac{7}{12}+\dfrac{0}{12}=\dfrac{3}{12}+\dfrac{4}{12}=\dfrac{5}{12}+\dfrac{2}{12}=\dfrac{1}{12}+\dfrac{6}{12}=\dfrac{1}{3}+\dfrac{1}{4}\\ \dfrac{17}{24}=\dfrac{0}{24}+\dfrac{17}{24}=\dfrac{1}{8}+\dfrac{1}{3}+\dfrac{1}{4}\)
Bài 5:
\(\dfrac{13}{15}-\dfrac{7}{15}=\dfrac{13-7}{15}=\dfrac{6}{15}=\dfrac{6:3}{15:3}=\dfrac{2}{5}\\ \dfrac{9}{24}-\dfrac{5}{24}=\dfrac{9-5}{24}=\dfrac{4}{24}=\dfrac{4:4}{24:4}=\dfrac{1}{6}\\ \dfrac{3}{4}-\dfrac{3}{12}=\dfrac{3\times3-3}{12}=\dfrac{9-3}{12}=\dfrac{6}{12}=\dfrac{6:6}{12:6}=\dfrac{1}{2}\\ \dfrac{16}{9}-\dfrac{18}{27}=\dfrac{16\times3-18}{27}=\dfrac{48-18}{27}=\dfrac{30}{27}=\dfrac{30:3}{27:3}=\dfrac{10}{9}\\ \dfrac{6}{7}-\dfrac{5}{7}+\dfrac{4}{7}-\dfrac{3}{7}+\dfrac{2}{7}-\dfrac{1}{7}=\left(\dfrac{6}{7}-\dfrac{5}{7}\right)+\left(\dfrac{4}{7}-\dfrac{3}{7}\right)+\left(\dfrac{2}{7}-\dfrac{1}{7}\right)=\dfrac{1}{7}+\dfrac{1}{7}+\dfrac{1}{7}=\dfrac{1+1+1}{7}=\dfrac{3}{7}\)
1:
2 3/4
5 6/5
3 3/9
7 6/8
2:
1/3 + 2/3 + (3/4 + 1/4) = 2
45\10
