# 小案例，打印输出加法口诀
for i in range(1,10):
    for j in range(1,10):
        if j>i:
             break
        print(f"{j}+{i}={j+i}".strip(),end='\t')
    print()
print('\n')

for i in range(1,10):
    for j in range(1,10):
        if j>i:
             break
        print(f"{j}x{i}={j*i}",end='\t')
    print( )
print('\n')

for i in range(1,10):
    for j in range(1,10):
        if j>i:
             break
        print(f"{i}-{j}={i-j}",end='\t')
    print( )
print('\n')