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Multiply near 100 Preview this Workbook

Gurujada

Multiply near 100

Multiply numbers like 98 × 97 in your head in four moves — and see how Gurujada notices a mistake and helps you fix it.

  • Length 5 min of video
  • Content 8 items in 3 Sections
  • Practice 17 practice questions
  • Schedule Self-paced · from 30 Sep 2026
  • For Anyone new to Gurujada: learners and teachers
K With Krishnamohan

What you'll learn 13

  • Read a near-100 product as two blocks: left and right.

  • Carry the hundreds of an overflowing right block into the left block.

  • Find each number's deficit from 100.

  • Use surpluses for numbers above 100.

  • Explain why the right block of a base-100 answer always has two digits.

  • Carry an overflowing right block.

  • State the four moves in order.

  • Multiply two numbers just above 100.

  • Use (100-a)(100-b) = 100(100-a-b) + ab to explain the left and right blocks.

  • Find and explain an error in written working.

  • Multiply two numbers between 90 and 99 mentally.

  • Recognise a dropped zero in the right block.

  • Write every base-100 right block with exactly two digits.

Try a lesson

Preview lesson 98 × 97 in four moves The video stops to ask you a question Preview lesson Why the four moves work

Course content

3 Sections · 8 items · 5 min video

Four moves below 100 4 items · 14 min

Document

Keep two digits on the right

2 min

Carry, and numbers above 100 2 items · 11 min · After the previous Section

Document

When the right block overflows

3 min

Practice

Stretch the method

8 min · 9 questions

For teachers: watch and correct 2 items · 6 min

How you'll learn here

  • Videos ask you Lessons stop at key moments with a question.
  • Wrong, and why Wrong options say what went wrong.
  • Vidya asks back Stuck? It asks you questions, never gives the answer.
  • A teacher sees it Your work reaches Krishnamohan.

About this Workbook

A 25-minute tour of Gurujada built around one mental-maths method. Watch a short video, read why the method works, practise with instant reasons for each mistake, check your understanding with Vidya, and — if you teach — see how a teacher watches a learner's journey and corrects it.

No sign-up is needed for the preview lessons and the first practice sheet. Join to keep your answers, unlock the second Section and try an understanding check.

Your teacher

K

Krishnamohan

Also teaches Beyond LeetCode · Lendi · Oct 2026 , How to Speak

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