Question

Suppose we write down the smallest (positive) $2$-digit, $3$-digit, and $4$-digit multiples of $7$.

Answer 1

Step-by-step explanation:

Smallest two digit number which is multiple of 7 = 14 (7*2)

Smallest three digit number which is multiple of 7 = 105 (7*15)

Smallest four digit number which is multiple of 7 = 1001 (7*143)

Sum = 14+105+1001 = 1120.