Lesson 8

Workshop: Multiplication with Larger Numbers

Est. Class Sessions: 2

Daily Practice and Problems

Teacher Notes

This item can be used as a Problem of the Week.

Square numbers between 6–150: 9, 16, 25, 36, 49, 64, 81, 100, 121, 144

Numbers one larger than the squares above (between 6 and 150): 10, 17, 26, 37, 50, 65, 82, 101, 122, 145

Numbers from the list above whose digits sum to a multiple of five:

37 (3 + 7 = 10),

50 (5 + 0 = 5),

82 (8 + 2 = 10)

122 (1 + 2 + 2 = 5)

145 (1 + 4 + 5 = 10)

Of these numbers, only 37 is a prime number. The others are divisible by 2 or 5.

I am a number between 6 and 150.

I am one more than a square number.

The sum of my digits is a multiple of 5.

I am prime.

What number am I? Explain your strategy.