2106-297+599                  145+263+55-19．

2106-297+599                  145+263+55-19．

（1）2106-297+599，=2100+6-300+3+600-1，=（2100-300+600）+（6+3-1），=2400+8，=2408；（2）145+263+55-19，=（145+55）+（263-19），=200+244，=444．

145 + 263 + 35-198 steps

145+263+35-198=(150-5)+(250+13)+35-(200-2)=150+250+13+35+2-5-200=245

How to simplify the calculation of 432-123-77?

432-123-77
=432-（123+77）
=432-200
=232
a-b-c=a-(b+c)

1.23 * 16.8 + 32 * 0.123 simple method

1.23*16.8+32*0.123
=1.23*16.8+3.2*1.23
=1.23*(16.8+3.2)
=1.23*20
=1.23*(10+10)
=1.23*10+1.23*10
=12.3+12.3
=24.6

|123/13|+|123/13+24/7|=?
Please

Yes, 22 (32 / 91)

123°24′-60°36′42〃

Angle plus minus 60
That is 123 ° 24 ′ - 60 ° 36 ′ 42 ″ = 62 ° 47 ′ 18“

If AB is reciprocal and a / 7 = x / B, what is 3A equal to?

How much is 3A = or 3x =?
If you ask x =?
The answer is as follows:
Because a / 7 = x / b
Then there is: 7x = AB = 1, so x = 1 / 7, then 3x = 3 / 7
If 3A =?
Because AB is reciprocal to each other, then a = 1 / B, then 3A = 3 / b

Uncle Li keeps chickens and rabbits in the same cage. Grandson Xiaoqiang asks grandfather, "grandfather, how many chickens and rabbits are there?" grandfather says with a smile, "there are 15 more rabbits than chickens, and there are 228 feet of chickens and rabbits. How many chickens do you have? How many rabbits do you have?" please calculate for Xiaoqiang

15 * 4 = 60
228-60 = 168
168 ÷ (2 + 4) = 28 (pieces) chicken
28 + 15 = 43 rabbit

There are 10 table tennis tables in the table tennis room. There are 32 people playing. How many tables are playing doubles? How many tables are playing singles?

There are x tables for doubles and Y tables for singles
X+Y=10,4X+2Y=32
The solution is x = 6, y = 4

Mother squirrel may pick 20 pinecones every day on sunny days, but only 10 on rainy days. He picked 120 pinecones for 10 days in a row. How many rainy days are there in these days?

Suppose all sunny days: 20 × 10 = 200
So the rainy days are: (200-120) / (20-10) = 8 days