IMSUB Function in Zoho Sheet: Syntax and Worked Examples

• Introduced: Listed in Zoho Sheet’s current function reference; the first introduction date or release remains unknown.
• Availability: Currently documented in the rolling web-service help; no final supported-version endpoint is established.
• Scope: Web documentation is the checked source. Mobile parity, old workbook behavior and exact imported-text handling are not separately established.
• Checked: October 14, 2026, against the official IMSUB entry. Examples independently calculated; no native Zoho Sheet test.

=IMSUB(complex_num1; complex_num2)

Both arguments are required complex-number text values or cell references containing those values. There is no default second operand and no documented third operand. For (a+bi)-(c+di), the result is (a-c)+(b-d)i.

Use lowercase i or j consistently within a pair. Zoho’s COMPLEX function constructs complex text from numeric real and imaginary coefficients and an optional suffix; the documented suffix default is i. For example, =COMPLEX(2;3;"j") creates 2+3j.

Quotation marks belong around a text literal inside a formula. When manually typing the value into a worksheet cell, enter 2+3j without enclosing quote characters. A reference such as A2 is not quoted: =IMSUB(A2;B2).

The examples use Zoho’s documented semicolon argument separator and decimal points. Complex text is not a native numeric pair that ordinary cell subtraction should be assumed to parse; use the complex functions.

In a blank worksheet, put First complex number, Second complex number, and Difference in A1:C1. Enter the following text in A2:B7, without enclosing quotes:

Enter =IMSUB(A2;B2) in C2 and fill through C7. Row 4 explicitly supplies 5j as its first operand rather than relying on an unexplained cell from an embedded vendor example.

A coefficient of one may be printed as j rather than 1j, and a zero result may omit the imaginary part. Compare the represented coefficients, not only the typography of the complex string.

In D1:E1 put Real coefficient and Imaginary coefficient. Enter =IMREAL(C2) in D2 and =IMAGINARY(C2) in E2, then fill both through row 7. Expected pairs are (1,1), (-4,-5), (-3,7), (2,2), (-6,8), (0,0). See IMREAL and IMAGINARY for numeric extraction.

Put =IMSUB(B5;A5) in H5. It reverses row 5 and represents -2-2i, rather than 2+2i. Subtraction is not commutative.

In G2 enter =IMSUM(C2;B2) and fill through G7. This adds each subtracted value back using IMSUM. The coefficients should match A2:A7. It is a useful check for swapped columns, copied references or a missing minus sign.

The reversal and add-back checks answer different questions. An add-back identity can expose a mistaken input reference, while the sign of the reverse result makes the operand order visible.

On a separate blank worksheet named Calibration, use headers Measured, Offset, Residual, Residual magnitude, and Restored in A1:E1. Enter the text 7+4i in A2 and 2-i in B2. Put:

• C2: =IMSUB(A2;B2), expected 5+5i.
• D2: =IMABS(C2), expected approximately 7.0710678119.
• E2: =IMSUM(C2;B2), representing the original 7+4i.

In F2 enter =IMABS(A2)-IMABS(B2). Its result is approximately 5.8261897708, which differs from D2. Subtracting two magnitudes is not the same operation as subtracting two complex vectors and then taking the magnitude. IMABS measures the length of the resulting complex number.

Both measured value and offset must describe compatible quantities, units and reference conventions before this model is meaningful. This arithmetic does not calibrate an instrument or establish the reliability of the original measurements.

• Keep an imaginary suffix on manually entered non-real values; 1-4 is not the complex text 1-4i.
• Keep each subtraction pair’s suffix consistent. The short IMSUB entry does not settle all mixed-i/j cases.
• Generic error tables mention incorrect names, missing quotes, invalid argument types and broken references. They do not establish an exact native error token for every malformed complex string.
• Do not replace the two scalar operands with a range and assume IMSUB becomes a running subtraction. Its documented signature has two arguments.
• Preserve full coefficients through intermediate calculations. A rounded displayed residual can hide a small discrepancy in an add-back check.