Упр.225 ГДЗ Ткачёва 6 класс (Математика)

1) 7,2 + 1 1/2; 2) 3,6 + 2 1/4; 3) 4,25 — 3 5/8;
4) 5 7/16 — 3,75; 5) 9 9/20 — 7,25; 6) 3,125 — 1 13/20.

1) $$7,2+1\frac{1}{2}=7\frac{2}{10}+1\frac{5}{10}=8\frac{7}{10}=8,7$$

2) $$3,6+2\frac{1}{4}=3\frac{6}{10}+2\frac{1}{4}=3\frac{3}{5}+2\frac{1}{4}=3\frac{12}{20}+2\frac{5}{20}=5\frac{17}{20}=5,85$$

3) $$4,25-3\frac{5}{8}=4\frac{25}{100}-3\frac{5}{8}=4\frac{1}{4}-3\frac{5}{8}=4\frac{2}{8}-3\frac{5}{8}=3\frac{10}{8}-3\frac{5}{8}=\frac{5}{8}=0,625$$

4) $$5\frac{7}{16}-3,75=5\frac{7}{16}-3\frac{75}{100}=5\frac{7}{16}-3\frac{3}{4}=5\frac{7}{16}-3\frac{12}{16}=4\frac{23}{16}-3\frac{12}{16}=1\frac{11}{16}=1\frac{11\cdot 625}{16\cdot 625}=1\frac{6875}{10000}=1,6875$$

5) $$9\frac{9}{20}-7,25=9\frac{9}{20}-7\frac{25}{100}=9\frac{9}{20}-7\frac{5}{20}=2\frac{4}{20}=2\frac{2}{10}=2,2$$

6) $$3,125-1\frac{13}{20}=3\frac{125}{1000}-1\frac{13}{20}=3\frac{1}{8}-1\frac{13}{20}=3\frac{5}{40}-1\frac{26}{40}=2\frac{45}{40}-1\frac{26}{40}=1\frac{19}{40}=1\frac{19\cdot 25}{40\cdot 25}=1\frac{475}{1000}=1,475$$

Ответ

1) 8,7; 2) 5,85; 3) 0,625; 4) 1,6875; 5) 2,2; 6) 1,475.