1. carry-free addition

1, 1 plus 4,5 doctors. ( 1+4=5 4+ 1=5)

2, 2 plus 3, 5 refers to the mountain. (2+3=5 3+2=5)

Three, two plus four, six monkeys. (2+4=6 4+2=6)

Four, three plus three, six cents. (3+3=6)

Five, three plus four, seven peaches. (3+4=7 4+3=7)

Six, four plus four, eight brothers. (4+4=8)

Seven, five, five, tiger. (5+5= 10)

Second, carry addition (right MINUS left, right MINUS a few, left hand remembers carry 1)

1, 1 and 9, hand in hand. 9 Go if you are in trouble 1. (Subtract 1 from 1) 1 It's hard to find 9. (minus 9 equals 1)

Two, two, eight are family. 8 have difficulty finding 2. (Reduce 2 to 1)2 is hard to find 8. (minus octal 1)

Three, three, seven, brothers. 7 found that 3 had difficulties. (minus 30% 1)3 is hard to find 7. (minus 7 decimal 1)

Four, four and six, good friends. 6 have difficulty finding 4. (minus 40% 1)4 is hard to find 6. (minus 6 hexadecimal 1)

Five, five, five, big tiger. If you are in trouble, go to 5. (Minus 5 equals 1)

Third, abdication subtraction (left plus right retreat, right hand plus a few, left hand remember to abdicate 1. )

1, 1 and 9, hand in hand. 9 Go if you are in trouble 1. (Add 1 and return 1) 1 It is difficult to find 9. (Add 9 to return to 1)

Two, two, eight are family. 8 have difficulty finding 2. (plus 2, minus 1)2 It is difficult to find 8. (plus 8 and back 1)

Three, three, seven, brothers. It is difficult to find it. (Add 3, back to 1)3 It is difficult to find 7. (positive 7 and negative 1)

Four, four and six, good friends. 6 have difficulty finding 4. (plus 4, minus 1)4 is hard to find 6. (plus 6 and back 1)

Five, five, five, big tiger. If you are in trouble, go to 5. (plus 5 and back 1)