690  Stamp
How many stamps? 1

Name : _________________

 

refresh

There are 230 stamps which are 6-cent stamps and 8-cent stamps. Altogether they cost 1560 cents. How many 6-cent stamps are there?



There are 220 stamps which are 7-cent stamps and 9-cent stamps. Altogether they cost 1780 cents. How many 7-cent stamps are there?



There are 230 stamps which are 7-cent stamps and 9-cent stamps. Altogether they cost 1770 cents. How many 7-cent stamps are there?



There are 210 stamps which are 7-cent stamps and 6-cent stamps. Altogether they cost 1360 cents. How many 7-cent stamps are there?



There are 200 stamps which are 7-cent stamps and 3-cent stamps. Altogether they cost 1040 cents. How many 7-cent stamps are there?



There are 250 stamps which are 8-cent stamps and 9-cent stamps. Altogether they cost 2130 cents. How many 8-cent stamps are there?



There are 170 stamps which are 6-cent stamps and 7-cent stamps. Altogether they cost 1120 cents. How many 6-cent stamps are there?



There are 230 stamps which are 8-cent stamps and 9-cent stamps. Altogether they cost 1960 cents. How many 8-cent stamps are there?



There are 170 stamps which are 4-cent stamps and 6-cent stamps. Altogether they cost 820 cents. How many 4-cent stamps are there?



There are 210 stamps which are 7-cent stamps and 6-cent stamps. Altogether they cost 1370 cents. How many 7-cent stamps are there?



+(         )

 

(         )+

++[[          ]]++

690    140 100 150 100 110 ( 600 )   120 70 110 100 110 ( 510 )   [[ 1110 ]]