Răspuns:10x9=90
10x5+10x4=50+40=90
9x8=72
3x8+6x8=24+48=72
7x7=49
7x9-7x2=63-14=49
Explicație pas cu pas:12) 1 32/49:(4 15/49-2 13/14)+(4,254-1,134:0,28)+
+1,114 =2,513
1. 4 15/49 - 2 13/14= 2 (30/98-91/98)= 2-61/98=
=1 (98/98-61/98)= 1 37/98
2. 1 32/49 : 1 31/98= 81/49:129/98=
=(81×98):(49×129)=(81×2):129=162/129=
=1,256
3. 1,134:0,28=4,05
4. 4,254 -4,05 =0,204
5. 2/3×0,204=0,7×0,204 =0,143
6 1,256+0,143 +1,114 =2,513
13) 4,58-(1,295 +1,936 :3 1/5)×1 16/19 +3 5/21:
:(4 4/34 - 3 19/56)=5,25
1. 1,936 :3 1/5=1,936:3,2=0,605
2. 1,295 +0,605 =1,9
3. 1,9 × 1 16/19= 1 9/10× 1 16/19=19/10×35/19=
=(19×35):(10×19)=35:10=3,5
4. 4 4/34 - 3 19/56= 1 (224/1904 -646/1904)=
= 1 -425/1904= 1904/1904 -425/1904=
= 1479/1904
5. 3 5/21 : 1479/1904 =68/21:1479/1904=
=(68×1904) :(21×1479) =129472 : 31059=
= 4,17
6. 4,58 -3,5 + 4,17=5,25
14) 12,5+(17,5-8,25×10/11)×(11 2/3: 2 2/9 +3,5)-
-12,6 ×2 1/2=130,63
1. 8,25×10/11=8 1/4×10/11=33/4×10/11=(33×10):
:(4×11)= 2/5=0,4
2. 17,5 -0,4=17,1 =
3. 11 2/3 : 2 2/9= 35/3: 20/9=(35×9):(3×20)=
=21/4=5,25
4. 5,25 +3,5=8,75
5. 17,1 ×8,75=149,63
6. 12,6 × 2 1/2=12 3/5× 2 1/2=63/5×5/2=
=(63×5):(5×2)=63/2=31,5
7. 12,5 +149,63 -31,5 =130,63
