Question

Calculați în două moduri:
a) 6,7-2,3;
b) 8,9-3,4;
c) 9,7-1,4;
d) 7,8-4,6;
e) 12,4-3,6;
f) 7-2,48.
Dau 100 de puncte!!! Cat mai rapid!!!

Answer 1

Răspuns:

a) 6,7-2,3=4,4

$\frac{67}{10} - \frac{23}{10} = \frac{44}{10} = 4.4$

b) 8,9-3,4=5,5

$\frac{89}{10} - \frac{34}{10} = \frac{55}{10} = 5.5$

c) 9,7-1,4=8,3

$\frac{97}{10} - \frac{14}{10} = \frac{83}{10} = 8.3$

d)7,8-4,6=3,2

$\frac{78}{10} - \frac{46}{10} = \frac{32}{10} = 3.2$

e)12,4-3,6=8,8

$\frac{124}{10} - \frac{36}{10} = \frac{88}{10} = 8.8$

f)7-2,48=4,52

$\frac{7}{1} - \frac{248}{100} = \frac{700}{100} - \frac{248}{100} = \frac{452}{100} = 4.52$

Explicații:

Prima metoda este prin calcul direct

A doua metoda am adus numerele sub forma de fractii si am calculat

Answer 2

Răspuns:

a) 6,7 - 2,3 = 67/10 - 23/10 = (67 - 23)/10 = 44/10 = 4.4

6,7 - 2,3 = (6 - 2) + (0.7 - 0.3) = 4 + 0.4 = 4.4

b) 8,9 - 3,4 = 89/10 - 34/10 = (89 - 34)/10 = 55/10 = 5.5

8,9 - 3,4 = (8 - 3) + (0.9 - 0.4) = 5 + 0.5 = 5.5

c) 9,7 - 1,4 = 97/10 - 14/10 = (97 - 14)/10 = 83/10 = 8.3

9,7 - 1,4 = (9 - 1) + (0.7 - 0.4) = 8 + 0.3 = 8.3

d) 7,8 - 4,6 = 78/10 - 46/10 = (78 - 46)/10 = 32/10 = 3.2

7,8 - 4,6 = (7 - 4) + (0.8 - 0.6) = 3 + 0.2 = 3.2

e) 12,4 - 3,6 = 124/10 - 36/10 = (124 - 36)/10 = 88/10 = 8.8

12,4 - 3,6 = (12 - 3) + (0.4 - 0.6) = 9 + (- 0.2) = 9 - 0.2 = 8.8

f) 7 - 2,48 = 700/100 - 248/100 = (700 - 248)/100 = 452/100 = 4.52

7 - 2,48 = (7 - 2) + (0 - 0.48) = 5 + (-0.48) = 5 - 0.48 = 4.52