1. The students drove for an autumn outing. There are 50 people in the first carriage. If the six students in the first car are transferred to the second car, there will be two fewer students in the first car than in the second car. How many people are there in the second car? I will do it in grade one! )

2. There are some chocolates in Box A and Box B. After taking out 9 chocolates from Box A and putting them in a new box, there are 5 more chocolates in Box A than in Box B. How many chocolates are there in Box B?

There are 50 chocolates in box A. After taking out 12 chocolates from box A and putting them in a new box, box A is better than box B..

There are still five chocolates in the box, and there are still a few in box B.

Arithmetic progression simple calculation

1、 1+2+3+4+5+6+7+8+9+ 10+ 1 1+ 12+ 13+ 14+ 15=

2、686+687+698+699+700+70 1+702+703+704=

2、 180+ 18 1+ 182+ 183+ 184+ 185+ 186+ 187=

Simple calculation by rounding method:

1、9+99+999=

2、9+99+999+9999=

3、9+99+999+9999+99999=