Simple calculation of 333 × 66.6 + 777 × 99.9 + 99.9

Simple calculation of 333 × 66.6 + 777 × 99.9 + 99.9

333×66.6+777×99.9+99.9
＝333×（0.3×222）＋777×99.9＋99.9
＝（333×0.3）×222＋777×99.9＋99.9
＝99.9×222＋777×99.9＋99.9
＝99.9×（222＋777＋1）
＝99.9×1000
＝99900

What is 100 + 99 + 65 + 66 + 98 + 26

100+99+65+66+98+26
=100+100-1+(65+25+1)+66+100-2
=300+66+90-2
=454

What are the rules in 5 * 7 = 35 6 * 11 = 66 72 / 2 = 36 88 / 8 = 11 50 / 10 = 5
quickly

5 * 7 = 35, multiplication formula,
6 * 11 = 66, single digit multiplied by 11, is a two digit list, a * 111111 = AAAAA
72 / 2 = 36, a number divided by 2 equals half of the number, and half of 72 is 36
88/8=11 ,AA/A=11,
50 / 10 = 5, when the single digit is 0, dividing by 10 is to remove the 0 of the single digit

(7.88+6.77+5.66)×（9.31+10.98+10）—（7.88+6.77+5.66+10)×（9.31＋10.

=10×（7.88+6.77+5.66)-10×（9.31＋10.98）
=203.1-202.9
=0.2