Question

calculati folosind factorul comun:25×13+52×8-25×11..7×8+2×7+9×10..37×28+42×37-42×15..207×28+207×180-208×206..19+19×9....15×99+15×13-15×112

Answer 1

25×13+52×8-25×11=
25×(13-11)+52×8=
25×2+52×8=
50+416=
466

7×8+2×7+9×10=
7×(8+2)+9×10=
7×10+9×10=
10×(7+9)=
10×16=
160

37×28+42×37-42×15=
37×(28+42)-42×15=
37×70-42×15=
2 590- 630=
1 960

207×28+207×180-208×206=
207×(28+180)-208×206=
207×208-208×206=
208×(207-206)=
208×1=
208

19+19×9=
19×(1+9)=
19×10=
190

15×99+15×13-15×112=
15×(99+13-112)=
15×(112-112)=
15×0=
0