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LEFT + LEN: mask the winners' phone numbers

Intan, who owns an online skincare shop, ran a giveaway and will announce the winners on Instagram. To protect privacy, phone numbers only show the first 4 and last 3 digits, and the rest is replaced with asterisks.

Task

In C2:C6, show the first 4 digits of the phone number, then one * for each hidden digit, then the last 3 digits. Example: 081234567890 becomes 0812*****890. The numbers have different lengths, so the number of asterisks must be calculated with LEN. Write it in C2 and copy it down to C6.

Cells to fillC2:C6

Required functionsLEFTLEN

Expected result

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Hint 1
LEFT(text, n) takes n characters from the left, RIGHT(text, n) from the right, and LEN(text) counts the characters.
Hint 2
Number of asterisks = length of the number minus 7 (4 in front + 3 at the end). REPT("*", n) repeats the asterisk n times.
Hint 3
Join the three parts with &: =LEFT(B2,4) & REPT("*", …) & RIGHT(B2,3).

Reveal them one at a time. The last hint nearly gives the answer away.

Give it a try first. The solution unlocks automatically after your first check.

Answer

C2:C6

=LEFT(B2,4)&REPT("*",LEN(B2)-7)&RIGHT(B2,3)

Write it in C2, then fill down to C6.

Explanation

=LEFT(B2,4)&REPT("*",LEN(B2)-7)&RIGHT(B2,3) gives 5 asterisks for a 12-digit number and 6 for a 13-digit number, so the result always has the same length as the original. The phone numbers are stored as text on purpose so the leading 0 is kept; stored as a number, LEFT would take "8123". Typing a fixed number of asterisks ("*****") is wrong for shorter or longer numbers.

Starting worksheet: Sheet1
Row	A	B	C
1	Winner	Phone number	Shown as
2	Nadia S.	081234567890
3	Ririn A.	08561122334
4	Dewi P.	0819876543210
5	Tasya M.	087788990011
6	Lala K.	08211234567
7
8
9
10
11
12
13
14

Fill in the requested cell, then press Check answer.

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