In this week’s blog post I thought I’d look at the rising prices of food. Like most of us I’ve noticed prices slowly rising over the weeks, particularly those of fish. Each week I buy a small packet of little prawns for sandwiches and the price of these have risen from £2.50 to £2.99. In general I’m not a great fish lover and tend to buy basa which is cheap white fish with little taste. My husband (Howard) fries it in lots of spices and self-raising flour to give it a nice crispy and tasty coating. For more expensive fish I imagine you’d want to taste the subtle flavours and would avoid a spicy coating. Anyway, we used to be able to buy six frozen basa fish for £3.50. Now they cost £4.00.

Prices are likely to rise and rise. In the UK we have been warned that domestic fuel prices could go up by at least 50% this year. Clearly, producers of food must also pay fuel bills so we can expect food prices to be affected everywhere.

I haven’t noticed such a large rise in the price of vegetables and am glad about this as the two of us are eating more vegetarian meals than we ever did. Part of the reason for this is that Howard has been on a diet and has lost a significant amount of weight by lowering his meat and carbs.

I will look at £4.00 in this blog post (or, to be more precise, 400 pennies).

The Forbes 400 2021

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The Forbes 400 list began in 1982 when Forbes magazine launched its list of the 400 wealthiest Americans. Those on the list are ranked by their net worth. In 2021 the list required a minimum net worth of $2.9 billion, up $800 million from 2020. Below are the top ten on the list. Please excuse the wobbly columns in this table: I am still getting used to WordPress.

RANK    NAME                                   NET WORTH       SOURCE                      PHILANTHROPY SCORE

1.            Jeff Bezos                            $201 B                  Amazon                         1

2.            Elon Musk                          $190.5 B               Tesla, SpaceX              1

3.            Mark Zuckerberg             $134.5 B               Facebook                       2

4.            Bill Gates                            $134 B                  Microsoft                    4

5.            Larry Page                          $123                     Google                            1

6.            Sergey Brin                        $118.5 B               Google                             1

7.            Larry Ellison                      $117.3 B               software                          1

8.            Warren Buffett                 $102 B                  Berkshire Hathaway       5

9.            Steve Ballmer                    $96.5 B                Microsoft                        2

10.          Michael Bloomberg         $70 B                    Bloomberg LP                 4

There are no real surprises about the top ten people on the Forbes 400. However, I was intrigued to see the philanthropy scores. The score rises from 1 to 5, with 5 representing the most generous. The scores are calculated by adding the value of each person’s total out-the-door lifetime giving to their 2021 Forbes 400 net worth and dividing their lifetime giving by that number. Those receiving a score of 1 means donations of less than 1% of net worth compared to 5 which means those who donated 20% or more. I was surprised that many of the top ten only scored a 1: when you have masses of money it’s far easier to give it away and yet it seems that many don’t. And, sadly, the Forbes 400 2021 philanthropy scores are lower throughout the list than they were in 2020 even though the wealth of billionaires has rocketed.

Harshad Numbers

In number theory, a Harshad number is an integer that is divisible by the sum of its digits. Harshad numbers were defined by the Indian mathematician D. R. Kaprekar. The term ‘harshad’ is a lovely description of a number property: the word “harshad” comes from the Sanskrit harṣa (joy) + da (give), meaning joy-giver and provides an inkling of how mathematicians feel when working with numbers that behave in a definable way.


The number 400 is a harshad number because 4 + 0 + 0 = 4 and 400 is divisible by 4 as 4 x 100 = 400.

The number 18 is a harshad number because 1 + 8 = 9 and 18 is divisible by 9 as 9 x 2 = 18.

The number 19 is not a harshad number because 1 + 9 = 10 and 19 is not divisible by 10.

Harshad numbers form the sequence:

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 18, 20, 21, 24, 27, 30, 36, 40, 42, 45, 48, 50, 54, 60, 63, 70, 72, 80, 81, 84, 90, 100, 102, 108, 110, 111, 112, 114, 117, 120, 126, 132, 133, 135, 140, 144, 150, 152, 153, 156, 162, 171, 180, 190, 192, 195, 198, 200 and so on.

I hope the number 400 has given you some joy today!

Final Thoughts

As we concern ourselves with rising prices and discover that many of the richest Americans are donating less of the wealth, we can hopefully find a little joy in number theory. 😊