Numbers Ideas - Deepstash


4 ideas

Multiplying 2 digit no.s ending with 1

Step 1: Since the no.s end with one our answer will contain the last digit as 1. Have that in mind.

Step 2: Now add both the tens digits i.e., (x + y) this is you tens place. (In case of double digit add it after step 3)

Step 3: Again take those two previous no.s and now multiply them i.e., (xy) this will give you the hundreds place in case of a single value or also a thousands place along with it if it is a double digit.

Finally put them all together and that's your answer

e.g 41 x 61

Ones digit:1

Tens digit:

ones digit: 1

tens digit: 10 so, 0 (1 will be carried)

Hundreds digit: 24

Final answer: 2501


Squaring numbers ending with 5

Squaring numbers ending with 5 is a simple trick that you must have in your sleeve.

Step 1: Multiply the ones digit. i.e., 5 x 5 = 25

Step 2: Multiply the no. and the next no. i.e n(n+1).

Now write the two no.s together and that's the final answer you'll obtain.

e.g 35^2

5 x 5 = 25

Now 3(3+1) = 3(4) =12.

Writing the no.s together we get the answer 1225. which is the square of 35.

Now try to re-trace the same pattern in the above picture.