Question 1
77 × 28 = ?
Crosswise multiplication — beat the clock.
- 1406
- 2144
- 1596
- 2156
- 2016
Show the worked solution
- Units: 7 × 8 = 56.
- Cross: 7×8 + 7×2 = 70; tens: 7 × 2 = 14 — stack with carries.
- 1400 + 700 + 56 = 2156.
- Answer: 2156.
Urdhva-Tiryagbhyam
Vedic maths multiplication tricks replace long multiplication with a crosswise pattern that produces the answer one digit at a time, right to left. For two-digit numbers, multiply the units, then cross-multiply and add, then multiply the tens — carrying as you go. The whole product is written in a single line with no intermediate rows.
Crosswise multiplication, or Urdhva-Tiryagbhyam, is the general Vedic method: unlike the base and complement tricks it works on any pair of numbers, which makes it the one worth learning first. In an exam it removes the two or three intermediate rows of long multiplication, and with them the transcription errors those rows invite.
Try it against the clock. Crosswise Multiplication runs at 20s easy, 30s medium and 45s hard. The clock is stamped and judged on our server, so the limit you see is the deadline that is actually enforced — and it starts when you tap Start, not while the question is loading.
For 43 × 21, multiply 3 × 1 = 3. That is the units digit of the answer. If the product exceeds nine, write the units digit and carry the rest into the next step exactly as in ordinary addition.
Multiply the tens of the first by the units of the second, and the units of the first by the tens of the second, then add: (4 × 1) + (3 × 2) = 10. Write 0 and carry 1. This crosswise step is the whole technique.
4 × 2 = 8, plus the carried 1 gives 9. Reading the digits produces 903. The answer emerged right to left in one line, with no intermediate products written down.
To multiply a two-digit number by 11, write the first digit, then the sum of both digits, then the last digit: 63 × 11 gives 6, 9, 3 — that is 693. If the middle sum exceeds nine, carry into the first digit. It is the crosswise method with the middle step made trivial.
| When the numbers look like this | Use |
|---|---|
| Any two-digit pair | Crosswise (Urdhva-Tiryagbhyam) |
| One number is 11 | Write outer digits, sum in the middle |
| Both just below 100 | Nikhilam — subtract the cross deficit |
| Same tens digit, units adding to 10 | Antyayordashake — one step |
| Equally spaced about a round number | Difference of squares |
| Number ends in 5, squared | Ekadhikena — n(n+1) then 25 |
Generated by the same engine that mints the ComputePrep daily. Each answer is computed from the numbers printed in the question, and the walkthrough below each one is the engine's own working — not a solution written afterwards. Reload this page's live drill and you get different numbers.
77 × 28 = ?
Crosswise multiplication — beat the clock.
29 × 42 = ?
Crosswise multiplication — beat the clock.
69 × 54 = ?
Crosswise multiplication — beat the clock.
The wrong options are not random numbers. Each one is the result of a specific careless error for this topic, so picking one tells you which habit is costing you marks.
The middle step routinely produces a two-digit total, and its tens digit must carry into the leftmost step. Losing it is the most frequent error when learning the method, and it shifts the answer by exactly one hundred.
Nikhilam and the complement methods only work on specific number shapes. Checking whether one applies costs time; the crosswise method always works. Learn crosswise as the default and treat the others as opportunistic.
A shortcut only pays if it is faster than the method it replaces, and early on it will not be. It needs timed repetition to overtake long multiplication — which is why every drill on this page runs on a clock.
Urdhva-Tiryagbhyam, meaning vertically and crosswise. You multiply the units digits, then cross-multiply and add the two middle products, then multiply the tens digits, carrying at each step. The answer forms one digit at a time from the right, with no intermediate rows to write down or misread.
The general crosswise method does, because it removes the intermediate rows of long multiplication where most transcription errors happen. The narrower tricks save more time but apply less often. The honest answer is that crosswise is worth learning for everyone and the base-specific sutras are worth learning once crosswise is automatic.
Write the first digit, then the sum of the two digits, then the last digit. For 63 × 11: 6, then 6 + 3 = 9, then 3, giving 693. When the middle sum exceeds nine, carry one into the leading digit — 87 × 11 gives 8, 15, 7 which becomes 957.
Crosswise multiplication, because it works on every pair of numbers rather than a special shape. Once it is automatic, add Ekadhikena for squaring numbers ending in five and Nikhilam for numbers near a base — both are faster but only apply sometimes.
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