Помогите вичеслить числа 90*25+10*25 123*27-23*27 23*16+16*27 40*87-39*87

1) 90*25+10*25 = (90+10) * 25=100*25=2500

2) 123*27-23*27 = (123-23) * 27=100*27=2700

3) 23*16+16*27 = (23+27) * 16=50*16=800

4) 40*87-39*87 = (40-39) * 87=1*87=87

90 * 25 + 10 * 25 = 25 * (90 + 10) = 25 * 100 = 2500

123 * 27 - 23 * 27 = 27 * (123 - 23) = 27 * 100 = 2700

23 * 16 + 16 * 27 = 16 * (23 + 27) = 16 * 50 = 800

40 * 87 - 39 * 87 = 87 * (40 - 39) = 87 * 1 = 87