Parallelogram 40 Level 1 6 Jun 2024Line multiplication

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Noun: Parallelogram Pronunciation: /ˌparəˈlɛləɡram/

  1. a portmanteau word combining parallel and telegram. A message sent each week by the Parallel Project to bright young mathematicians.
  • Tackle each Parallelogram in one go. Don’t get distracted.
  • Finish by midnight on Sunday if your whole class is doing parallelograms.
  • Your score & answer sheet will appear immediately after you hit SUBMIT.
  • Don’t worry if you score less than 50%, because it means you will learn something new when you check the solutions.

1. Line multiplication

There are loads of tricks we can keep up our sleeve to make calculation easier.

It all comes down to selecting the right tool for the right calculation.

Check out this quick and easy method for multiplying numbers using only lines!

(If you have problems watching the video, right click to open it in a new window)

1 mark

1.1 Which calculation would this method be most appropriate for?

  • 9,999 × 8,989
  • 24 × 13
  • 365 + 675
  • 16 × 19 × 24 × 65
  • (Not answered)
2 marks

1.2 Have a go at using this method to calculate 23 × 32

Show Hint (–1 mark)
–1 mark

23 × 32 can be visualised as follows:

Correct Solution: 736

1 mark

1.3 The method above relies on being able to quickly count up the dots at the intersection.

Let’s see how quick you are at counting - count these oranges as fast as you can!

Correct Solution: 16

(Image credit: Howie Hua on Twitter)

You can make life easier for yourself by moving the rightmost orange from the row of 5, into the row that only containts 3 oranges.

This makes for 4 rows of 4 oranges, giving 16 oranges.

Maybe you had another interesting way of counting them.

2 marks

1.4 The video explains how the line multiplication method extends to three-digit numbers.

Which calculation is shown in this image?

  • 123 × 124
  • 124 × 321
  • 124 × 312
  • 132 × 431
  • (Not answered)

2. Assembling Albert Einstein

2 marks

2.1 I was given a 1500-piece jigsaw of Albert Einstein.

Half the pieces are missing, and half of the rest are damaged.

How many good pieces are there?

  • 0
  • 350
  • 375
  • 500
  • 750
  • (Not answered)

3. A factor fact

2 marks

3.1 Which number is NOT a factor of 101,010?

  • 2
  • 3
  • 5
  • 7
  • 11
  • (Not answered)

Before you hit the SUBMIT button, here are some quick reminders:

  • You will receive your score immediately, and collect your reward points.
  • You might earn a new badge... if not, then maybe next week.
  • Make sure you go through the solution sheet – it is massively important.
  • A score of less than 50% is ok – it means you can learn lots from your mistakes.
  • The next Parallelogram is next week, at 3pm on Thursday.
  • Finally, if you missed any earlier Parallelograms, make sure you go back and complete them. You can still earn reward points and badges by completing missed Parallelograms.

Cheerio, Simon.