What is the missing number in each of these patterns?

Ten million. Age 11-13

When two numbers are multiplied together the answer is 10 000 000

Neither of the two numbers contains a zero. What are they?

Brainteaser solutions

Number patterns

a. The difference between the numbers is the sequence of square numbers.

The missing number is 55

b. Working towards the middle from each end, matching pairs of numbers add up to 40. The missing number is 24.

c. These are consecutive primes in reverse order. The missing number is 19

Ten million

78125 and 128