42 x 13 - 22 x 5 + 42 x 7 - 15 x 22
= (42 x 13 + 42 x 7) - (22 x 5 + 15 x 22)
= [42 x (13 + 7)] - [22 x (5 + 15)]
= 42 x 20 - 22 x 20
= 20 x (42 - 22)
= 20 x 20
= 400
\(42\cdot13-22\cdot5+42\cdot7-15\cdot22\)
\(=42\cdot\left(13+7\right)-22\cdot\left(5+15\right)\)
\(=42\cdot20-22\cdot20\)
\(=20\cdot\left(42-22\right)\)
\(=20\cdot20\)
\(=400\)
\(42\cdot13-22\cdot5+42\cdot7-15\cdot22\)
\(=42\cdot\left(13+7\right)-22\cdot\left(15+5\right)\)
\(=42\cdot20-22\cdot20\)
\(=20\cdot\left(42-22\right)\)
\(=20\cdot20\)
\(=400\)
42.13-22.5+42.7-15×22
=42.(13+7)-22.(15+5)
=42.20-22.20
=(42-22).20
=20.20
=400