Question

repede va rog! dau coroana​

Answer 1

1. 4x20=4x(10x2)
=(4x2)x10

=8x10

=80

2.50x3=3(10x5)

=(3x5)x10

=15x10

=150

3.90x2=2x(9x10)

=(2x9)x10

=18x10

=180

4.15x4=4x(3x5)

=(4x3)x5

=12x5

=60

5.7x19=7x(19x1)

=(7x1)x19

=7x19

=133

6.6x34=6x(17x2)

=(6x2)x17

=12x17

=204

7.77x2=2x(7x11)

=(2x7)x11

=14x11

=154

8.88x2=2x(8x11)

=(2x8)x11

=16x11

=176

9.3x55=3x(5x11)

=(3x5)x11

=15x11

=165

10.7x50=7x(10x5)

=(7x10)x5

=70x5

=350

11.60x4=4x(10x6)

=(4x6)x10

=24x10

=240

12.70x3=3x(10x7)

=(3x7)x10

=21x10

=210

13. 25x3=3x(5x5)

=(5x3)x5

=15x5

=75

14. 34x5 = 5x(17x2)

=(5x2)x17

=10x17

=170

15. 81x4 = 4x(9x9)

=(9x4)x9

=36x9

=324

Answer 2

4×20=4×(2×10)=(4×2)×10

8×10=80

50×3=3×(5×10)=(3×5)×10

15×10=150

90×2=2×(9×10)=(2×9)×10

18×10=180

15×4=4×(5×3)=(4×5)×3

20×3=60

7×19=7×(19×1)=(7×19)×1

133×1=133

6×34=6×(17×2)=(6×17)×2

102×2=204

77×2=2×(11×7)=(2×11)×7

22×7=154

88×2=2×(4×22)=(2×4)×22

8×22=176

3×55=3×(5×11)=(3×5)×11

15×11=165

7×50=7×(5×10)=(7×5)×10

35×10=350

60×4=4×(6×10)=(4×6)×10

24×10=240

70×3=3×(7×10)=(3×7)×10

21×10=210

25×3=3×(5×5)=(3×5)×5

15×5=75

34×5=5×(17×2)=(5×17)×2

85×2=170

81×4=4×(9×9)=(4×9)×9

36×9=324